BPG Parchment Conservation Treatment

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Book and Paper Group Wiki > Paper Conservation Wiki > Parchment Conservation Treatment

This page covers the treatment of parchment. See also: BPG Parchment, BPG Parchment Condition Problems, BPG Parchment Examination and Documentation, BPG Parchment Housing and Storage, and BPG Parchment Historic Treatment Methods and Materials.

Wiki Compiler: Cathie Magee
Wiki Contributors: your name could be here

Copyright 2025. The AIC Wiki is a publication of the American Institute for Conservation (AIC). It is published as a convenience for the members of AIC. Publication does not endorse nor recommend any treatments, methods, or techniques described herein. Information on researching with and citing the wiki can be found on the Reference and Bibliography Protocols page.

Cite this page:

American Institute for Conservation (AIC). "BPG Parchment Conservation Treatment." AIC Wiki. May 20, 2025. https://www.conservation-wiki.com/wiki/BPG_Parchment_Conservation_Treatment.

Factors to Consider

Understanding the physical properties of parchment is key to anticipating how it may behave in certain conditions and during treatment procedures.

Physical and Chemical Stability

Parchment is usually a very strong and durable material that is usually resistant to physical forces such as surface abrasion, creasing and tearing. (Modern parchments made from the inner splits of sheepskins have little tear strength, however, because they lack the tightly connected fiber structure of the grain layer.) Parchment is more resistant than paper to corrosive inks and paints, yet perforation of the support can ultimately occur in the presence of moisture. Parchment is susceptible to biological attack and, in extreme circumstances, the collagen structure can be completely degraded in the presence of mold. Parchment is not as prone to acid degradation as is paper, due in part to alkaline agents such as lime and chalk that are used in the manufacturing process.

(Clarkson 1992) Vorst?

Hygroscopicity

The extremely hygroscopic nature of parchment makes it dimensionally unstable, causing it to expand and contract in response to changes in the surrounding environment. This often leads to distortion or cockling of the sheet and other dimensional changes which can range from minor to severe, depending on the surrounding environmental conditions. Treatment goals can often be affected by the extreme reactivity of parchment to changes in relative humidity, particularly when treatments involving the use of moisture are being considered. Methods used for the housing and display of parchment artifacts must also include consideration of its hygroscopic nature. (See

Media found on parchment are often affected by the reactivity of the support to changes in relative humidity, especially in cases where the paint or ink may be brittle and/or thickly applied. The expansion and contraction of the parchment support usually occurs at a faster rate, thus putting stress on the media. If the media is unable to respond to extreme stress it will begin to crack and eventually flake off the parchment surface. These issues need to be considered when undertaking treatments involving moisture and when choosing environmental conditions for storage and display.

Thermal Reactivity

The effects on parchment to both dry and moist heat are important features to consider. According to Reed (1972, 316-318), parchment can withstand a dry oven temperature of 100C almost indefinitely without any obvious changes in color, dimension or shape. Once removed from the oven the skin absorbs moisture from the atmosphere and is able to regain its original handling properties. Heating parchment at higher temperatures has a more dramatic effect, with 130-150C being a critical temperature at which intense curling and browning occur.

Moist heat has a much more dramatic effect on parchment than dry heat. The addition of moisture causes the collagen fibers in parchment to swell and then rapidly contract. This phenomenon, which is often used to determine the relative age of a piece of parchment, is referred to as the shrinkage temperature. Ancient parchments have collagen fibers that are more degraded and hence they shrink at much lower temperatures than modern skins. (For more information on this subject see Reed 1972, 313-316, Haines 1987, Young 1990, and Young 1992.)

Potential Alteration/Damage to Object in Treatment

[Copied from original BPG Parchment wiki page]

Many traditional paper conservation techniques can result in irreversible alteration of an artifact when applied to parchment. In addition, because of its animal origin, parchment can often respond to accepted treatment methods in unpredictable ways. The conservator's approach to the treatment of parchment must therefore be extremely cautious, especially if one has little or no previous experience in a particular treatment procedure. In order to avoid taking risks, and endangering the safety of the object, sometimes the best approach is little or no treatment at all.

Problems Caused by Water or Excessive Moisture: expansion of the object beyond its original dimensions; increased darkening and discoloration of skin already damaged by mold; softening and/ or solubilizing of media resulting in offset onto adjacent materials (felts, blotters, etc.); alteration of surface preparations and coatings; removal of the lime and/ or chalk resulting in a translucent appearance similar to rawhide; in severe cases of water exposure, realignment of the fiber bundles to a random pattern (rather than parallel to the surface) resulting in a stiff, horny, translucent skin; translucency resulting from overly damp skin being dried under no tension at all; gelatinization of an already degraded skin.

Problems Caused by Excessive Pressure: introduction of translucency/transparency in a damp skin; increased stiffness and inflexibility; reduction of printing impressions, platemarks or embossings; flattening or offsetting of media.

Problems Caused by Excessive Tensioning: expansion of object beyond original dimensions; change in platemark dimensions; weakening of media attachment; introduction of splits or tears; increase in translucency of skin.

Problems Caused by Use of Heat: irreversible contraction/shrinkage of the skin; damage to the collagen structure; alteration of surface preparations and coatings; alteration of media.

Problems Caused by Use of Steam: irreversible contraction/shrinkage of the skin; gelatinization and other damage to the collagen structure; alteration of surface preparations and coatings; weakening of media attachment; alteration or dissolving of media. (Steam is extremely dangerous and should never be used on parchment!)

Problems Caused by Use of Lubricants: alteration of surface texture and handle of skin; alteration of media (especially saturation of matte pigments); increase in transparency and in attraction of surface dirt; change in original dimensions of object.

Problems Caused by Use of Organic Solvents: in discolored skins, degradation products may be solubilized with the introduction of ethanol, resulting in tide lines; alteration of media; alteration of surface preparations and coatings; possible damage to collagen structure.

Problems Caused by Improper Housing Methods: failure of mount due to misinterpretation of string mat or other mounting technique; failure of mount and possible damage to artifact caused by housing that does not allow for expansion and contraction of parchment; failure to support weight of pendant seals, resulting in damage; loss of friable media and damage to pulpy degraded parchment when unsuitable housings are employed.

Other Factors to Consider

Substrate: Is this object really parchment? See BPG Parchment Examination and Documentation–Parchment vs. Paper.

Damage vs use: Cockling, pleating, transparency, stiff areas, gelatinization due to water damage (important to distinguish from naturally transparent areas); abraded areas (important to distinguish from corrections made by scribe or artist using a knife or other abrasive tool); punctures, tears and cuts (important to distinguish from cuts made intentionally by scribe or binder to flatten out natural cockling in skin); repairs (same issues involved); stains and accretions; mold damage; perforation/corrosion caused by acidic media, etc.

Factors to Consider References | top

Surface cleaning

[This section is edited from original BPG Parchment page] (See BPG Surface Cleaning)

If a parchment artifact is in good condition, dry cleaning methods are preferred over aqueous mixtures as the conservator wants to avoid wetting the skin in any way. The aqueous techniques discussed below are only performed in specific circumstances. Just as in cleaning paper, before undertaking any surface cleaning of parchment the conservator should weigh the benefit to the artifact against possible risk to the parchment surface or the media. A dry, healthy skin may permit more aggressive surface cleaning than paper would because the surface is more resistant to abrasion. This is especially true when the parchment surface is hard and smooth. In that case, however, it is important to consider whether the surface shininess is due to preparation or a surface coating that may be damaged or altered by cleaning actions or materials. Also, do not be tempted to go too far in local areas when a whole sheet cannot be safely or successfully cleaned. Use extreme caution when cleaning the margins of medieval manuscript leaves — these can contain ruling lines drawn in lead point that are often imperceptible to the naked eye. Nineteenth century prints and drawings that are on split skins can be fragile and prone to tearing during surface cleaning if there are small cuts or tears at the edges. Surface cleaning of a degraded parchment may be too risky to undertake.

Materials

• Optivisor, magnifier, or binocular microscope
• Latex-free polyurethane sponges
• Soft brushes
• Erasers: vinyl block (white plastic), crepe (rubber), kneaded (unvulcanized rubber)
• Microspatula, Teflon spatula, Casselli knife, scalpels, tweezers
• HEPA vacuum, fume hood, PPE

Surface Grime

See BPG Parchment Condition Problems > Surface grime for types of surface grime and whether removal is appropriate.

Overall and/or localized surface grime is a frequent occurrence on parchment artefacts. Dust and dirt from the environment (so-called museum grime) readily accumulates on the edges of books not stored in boxes and on the exposed faces of folded documents. This grime tends to be loose and transfers easily to other areas of the object, to other objects, to the work surface, and to the conservator, making its removal common first step in treatment. However, the fibrous and porous nature of the parchment membrane means that dry cleaning rarely results in these objects appearing cleaner. So-called historic dirt from handling or very long-term exposure is especially ingrained, though may be essential to the story of the object and its removal may not be desired.

Latex-free polyurethane (cosmetic) sponges are an excellent choice for surface cleaning parchment that is in good condition, as they trap the grime as it is removed. Soft brushes can be used for damaged parchment, but if the object is delicate it is alright to question the need to clean at all. Areas of heavy grime may be addressed with a solid eraser, but use caution to prevent disturbing the parchment fibers. Eraser crumbs may end up trapped in parchment fibers.

Wet cleaning is rarely done as the direct introduction of moisture always poses the risk of damaging the parchment, such as permanently flattening a suede surface or altering a surface coating. Certain organic solvents (such as petroleum benzine) can be especially useful for removing greasy soot and ingrained dirt. Over-dampening with solvent should be avoided to prevent solubilizing components of the parchment. Sometimes organic solvents are diluted with water (50% water or less) to improve cleaning activity. Local areas that have been surface cleaned with aqueous solutions should be immediately weighted to avoid excessive cockling. Magee (2019) has experimented with cleaning gels and the Modular Cleaning Program solvents on a parchment binding.

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Mold remediation

(See BPG Mold)

As with paper, there is no substitute for good housekeeping in combating biological attack. Humidity and temperature in storage areas should not exceed...

If active mold is discovered, its removal should be carried out before any other treatment step to prevent further contamination of the object and the workspace. However, it can be done in conjunction with surface cleaning. It is especially important that it precedes other treatment steps including consolidation, humidification, or flattening to avoid making the removal of mold growth more difficult or impossible. Mold-damaged parchment is subject to mold reactivation if it is left in a humidity chamber or damp pack too long. Appropriate safeguards include:

• Personal protective equipment (PPE) such as gloves, apron, and mask or respirator should be worn.
• Ideally, the work should be carried out in a fume hood. If that is not available, work in a well-ventilated space.
• Sweep mold with a soft brush into a vacuum equipped with a HEPA filter. Do not use that brush for anything else.
• Consider cleaning moldy parchment with cotton dampened with an organic solvent such as ethanol to remove mold growth. This may be most effective if the parchment is still wet.

Mold grows down into parchment fibers and discolors the interior of parchment, beyond the reach of surface cleaning, and can remain dormant for long periods until a damp environment favors its regeneration. Permanent discoloration is likely. Erasers are inappropriate when mold is on the surface, as they will grind mold spores further into the parchment. They might sometimes be useful for deeper cleaning after surface growth has been brushed or vacuumed away.

Media effected by mold growth may be quite unstable as the binder is often degraded by mold. Media or especially degraded moldy parchment may benefit from "washing" with alcohol on the suction table prior to consolidation because of the reputed fungicidal property of the solvent (Maggen 1991). The use of solvent, however, will not prevent mold growth in the future.

Any fumigation technique suspected of having damaging effects on paper should be suspected of also being unsafe for parchment. Fumigants which affect organic materials may damage parchment irreversibly; an example reported by Szczepanowska (1992) is ethylene oxide, which may result in loss of adhesion of gum arabic and animal glues and can cause a cross-linking reaction with proteins. Fuchs et al. (1988) reports severe damage to pigments, especially vegetable dyes, in experiments exposing colors produced according to medieval recipes to formalin and ethylene oxide. Some colors shifted in hue, some changed completely (e.g. from red to green), and some sank into the parchment supports and penetrated to the reverse. Finally, the increased sensitivity of parchment to heat may make it even less suitable than paper for exposure to processes where heat is involved, such as thymol chambers and microwave radiation.

Accretions

Careful removal of accretions with a scalpel or spatula under magnification is often the simplest and least hazardous method. If this cannot be accomplished without damage to the underlying surface, it may still be desirable to thin an accretion before attempting to soften the residue for removal. Methyl cellulose is especially suitable for softening water-sensitive accretions because of its tendency to restrain the penetration of moisture and therefore will affect the underlying parchment to a lesser degree. Some conservators prefer saliva or thick starch paste for this purpose. When prolonged exposure to solvent is required, a solvent-based gel like Carbopol may be useful as a poultice. (Citations needed)

Before removing accretions, it is important to make sure that they are not intentional marks. For example, the diacritical marks in a Hebrew or Arabic manuscript can be easily mistaken for flyspecks. It is also important to consider whether the accretions may contain some codicological evidence, especially in the case of archaeological or religious material, or whether they may be evidence of use in an original context, such as wax drops from burning candles used for reading. If an accretion is not doing active harm to the object, it is usually fine to leave them. (Citations needed)

Adhesive Residues

Adhesive residues are typically found on the spine folds of parchment codices. They may also be found on lifted pastedowns, fragments, or under folio patch repairs that have fallen off. Removal or reduction of adhesive may be done if an extant adhesive layer, most often hide glue or a mixture of animal glue and paste, is in the way of further necessary treatment. A dry, smooth, healthy skin may be able to support the stress of scraping or chipping away a layer of adhesive on its surface when it forms a discrete layer (i.e. it has not penetrated the parchment fibers).

Sometimes it may be preferable to soften these adhesives using direct application of controlled moisture, such as damp swabs, methyl cellulose poultices, or gels. Inclusion of a neutral salt in directly applied moisture to raise the conductivity of the deionized water can be beneficial and speed up the softening of the adhesive (Magee 2019). If the parchment is to be humidified for flattening (overall or locally with Gore-Tex and blotters), it may work better to plan to remove softened adhesive after overall humidification but before tensioning or weighting. This can be done in stages, rehumidifying the parchment each time it begins to dry out, but must be done carefully to avoid marring the softened skin. (Use only straight deionized water to humidify. Do not humidify parchment with conductivity-adjusted salt water to soften adhesive.)

Some adhesive remnants may contain codicological or historical evidence. In other cases, adhesive removal may create undue risk or inevitably damage an artifact, such as when an adhesive covers media. Reducing the adhesive layer manually with a scalpel, leaving the last thin residue to the point that it will not cause puckering or other deformations over time, should be considered. This may be less hazardous to the long-term preservation of a naturally alkaline parchment than it would be in the case of a paper artifact. Sometimes residues may look disturbing when a somewhat translucent or thin parchment is viewed by transmitted light, but when the sheet is mounted or framed against a suitably light or dark support this unevenness will be disguised. One should only consider using moisture with heat if it is absolutely necessary and on especially intractable adhesive. Heat and moisture combined risk causing the protein fibers in parchment to decompose, leading to the gelatinization of the parchment matrix. Be especially cautious in this pursuit. A Preservation Pencil (from University Products) which delivers a slightly warmed mist has been successful for the initial softening of thick deposits of animal glue (citation needed). Avery (2019) has used a poultice with a heating pad on an oversize codex spine to soften the adhesive before manual removal.

Gelatin applied as an overall consolidant...

Some manuscripts that have been treated within the last 50 years have been treated with modern adhesives such as soluble nylon, polyvinyl alcohol, and polyvinyl acetate.

Where the media permit, some adhesives can be reduced or softened using cotton dampened with organic solvent and then removed mechanically. Solvent baths might be considered under extreme circumstances, but the potential for damage to the parchment structure and media must be weighed.

Tape

(See BPG Hinge, Tape, and Adhesive Removal)

Both pressure-sensitive and adhesive tapes are found on parchment as repairs and mounting material (with fragments). Purely physical methods of removal may be preferred for tapes on hard, smooth parchment surfaces. Remaining tape carriers can be removed with a scalpel or spatula. Sticky tape residues may be scraped off with a tool or picked up with the judicious use of a crepe eraser. In extreme cases, the fragile nature of delicate parchment or where tape is placed over media may make tape removal too damaging to undertake and it may be safer to leave the tape in place. (Citations needed)

Parchment that is very thin, degraded, mold-damaged, or prepared with delicate surface coatings can withstand little physical stress and may require more reliance on solvent activity. Organic solvents can soften intractable tape adhesive residues; if possible, take a sample of the adhesive to perform solubility testing rather than test directly on the object. Exposure to solvent fumes in a closed vapor chamber can soften adhesive and facilitate its removal with a spatula, scalpel, or other scraping tool. Several rounds in a vapor chamber may be needed to adequately soften the adhesive. For small areas, local exposure to solvent via plaster chambers can be used. Direct application of solvent may occur via brush, swab, or gel/poultice before removal of tacky adhesive with a crepe eraser, scraping tool, etc. Heat is generally not recommended for adhesive removal because the working temperatures of contact heating tools and hot air blowers may cause permanent damage to parchment. (Citations needed)

Stain Reduction

Purely aesthetic surface cleaning treatments such as stain reduction should be done rarely.

Surface Cleaning References | top

Humidification

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[copied from BPG Parchment]

Parchment must be humidified in order to make it responsive to any flattening/tensioning/drying treatment which follows. This is most often done in order to reduce the distortions in a skin. Markedly cockled, shrunken, or puckered skins can be difficult to read and visually disturbing. They are also subject to increased abrasion, which is a particular concern in cases where the sheets are in direct contact with each other as they are in a book or in a multi-sheet document. The improved flexibility of skins that have undergone this treatment contributes to their safety in storage, housing, and handling. Also, sometimes it is necessary to humidify a skin in order to make it possible to join a tear in a distorted area.

Humidification should always be carefully controlled and monitored, and not carried beyond what is necessary. Some conservators monitor the water content of the skin with a surface electrode before, during, and after humidification and also during drying. (Aqua-Boy, Sovraign and the Digital Mini Protimeter from Museum Services are three brands currently in use). Most conservators, however, rely on visual observation and manual testing of the flexibility of the skin in order to decide when the humidification is sufficient. Over-humidification can lead to permanent alteration of the skin, surface preparation, or media (see Potential Alteration/Damage to Object in Treatment: Problems Caused by Water or Excessive Moisture) and can make the skin much more susceptible to damage during pressing or tensioning (see Potential Alteration/Damage to Object in Treatment: Problems Caused by Excessive Pressure and Problems Caused by Excessive Tensioning.)

Controlled drying, using one of several techniques described in 18.4.10 Flattening/Drying/Tensioning, must always follow overall humidification. If the parchment is allowed to dry unrestrained, it will certainly cockle, and will probably be permanently altered. As an alternative to overall humidification, sometimes tears needing repair and isolated distortions can be locally humidified and dried. (See Local Treatment.)

The method chosen for humidification should take into account many factors, including the type, thickness, and condition of the skin, surface preparations, media, the goal of the treatment, and the quantity of material to be treated. Before beginning humidification it is important to consider what drying method will be used and have all tools and equipment ready. A delay may cause an artifact to become overly hydrated or to dry too quickly.

Vapor Chamber

Humidification chambers are designed to expose parchment artifacts to water vapor in a closed environment (Weidner 1993). The time necessary to hydrate a skin depends on many factors, including the quantity of material in the chamber, the type, thickness, the condition of the skin, and the design of the chamber. The process should be slow, to allow even, overall expansion. Cains (1982) suggests “85–95% RH in the humidification chamber, to achieve a moisture content in the skin of 22–28% for initial tensioning and 15–20% for final flattening and repair.” (See Forde 1986, p. 39.) There are not, however, firm guidelines which dictate the level of moisture required in a chamber, since different types of skin or areas of a skin (such as deteriorated areas of mold-damaged skin) absorb moisture at different rates. The humidification process should be monitored closely to guard against over humidification, and to ensure that condensation does not form inside the chamber causing moisture to drip onto the artifact, where it could damage the media, the surface preparation, or the parchment itself. Many conservators place an additional protective layer such as Gore-tex, polyester web and/or a blotter on top of the parchment in order to guard against this hazard. If glass is used to cover the tray, it can be pre-wiped with a treated cloth, designed to prevent condensation on the interior of windshields. Extreme caution is needed when humidifying mold-damaged skin, and a faster humidification method such as the “damp pack” (see below) may be safer.

Covered Tray

With Damp Blotters: Damp blotters line the bottom of a deep tray. The object (which is sandwiched between polyester webbing) is suspended over the blotters on a permeable and non-wicking material such as a light diffuser panel or a plastic screen. A damp blotter on top of the sandwich will accelerate the humidification process, if desired. The tray is then covered with Plexiglas in order to create a closed environment.

With Water: A tray of cold water can be placed in the bottom of a larger tray. The object is suspended above the smaller tray on a rigid permeable support such as a light diffuser panel or a stretched plastic screen, and the larger tray is covered with Plexiglas to close the chamber.

With Saturated Salt Solutions: With a saturated salt solution, the humidity in a chamber can be set to a very specific level.

Gore-Tex Systems

The very small pore size of the Gore-Tex laminate allows only water vapor to penetrate through to the skin (see Purinton and Filter, 1992). However, Gore-Tex is a fragile material and the user should take certain precautions. Through time and use, minuscule breaks or punctures can occur in the fabric, thereby allowing more moisture to pass in that particular area. To locate these areas of concern, the conservator should carefully examine the material before using by holding it up to a light. The weak or perforated areas will allow the light to pass through. To prevent accidental leaks either a second layer of Gore-Tex or polyester interleaving should be used. As with any humidification technique it is important to have the flattening and drying materials prepared in advance and to work quickly during tensioning because some conservators feel that parchment humidified with Gore-Tex dries faster. (Singer 1992.)

One-Sided Humidification: The Gore-Tex is laid on the artifact with the Teflon side down, and the felt side away. The usual moisture source is a damp blotter laid on top, although water could also be sponged or sprayed directly on the felt side of the Gore-Tex. For added protection a polyester web can be placed between the artifact and the Gore-Tex. A light weight, such as a felt or sheet of Plexiglas, can be laid on top of the package to help keep the layers in contact with each other. This weight should be minimal to avoid forcing excess moisture through the Gore-Tex, endangering the artifact.

This method of humidification offers increased control and is useful for treating single objects, and those with particularly sensitive media when it is desired to reduce the exposure of the recto to moisture. This method is preferable to humidifi-cation methods that utilize pressure such as a damp pack for objects with painted or gilded surfaces. Gore-Tex has been used successfully to humidify attached, multiple sheets such as charters which cannot be separated, isolating the adjacent sheets from the moisture with polyester film. It can also be used for humidifying individually skins which are joined to compose a larger sheet. Small pieces of Gore-Tex can be used for local humidi-fication within a sheet. (See Local Treatment.)

Two Sided Humidification: Two-sided (sandwich) humidification can be used for faster and more thorough humidification of a skin, by placing Gore-Tex and interleaving layers both above and below the object. To make a sandwich, place the dampened Gore-tex (felt side down/smooth side up) on a waterproof table surface. For added protection, layer thin Gore-tex and polyester interleaving, then object, multiple sections, etc., more interleaving, thin Gore-tex and then the dampened Gore-tex (felt side up, smooth side towards object). Cover all with Mylar or polyethylene sheeting and weight edges to “seal” humidity. For objects with sensitive media there is minimal weight and pressure. If the object(s) can withstand more contact, drape sandwich with 1/2" or 3/4" felts.

Damp Blotter Pack

Sheets of blotting paper are soaked in water and then drained. They are then interleaved with dry blotters of the same size and pressed under firm weight until moisture is evenly distributed throughout the pack. No liquid water should be present. The artifact is sandwiched between two pieces of polyester web and then inserted between two or more sheets of damp blotter on each side. The package is put between pressing boards and under moderate weight for less than five minutes. The object is then taken out and checked for its state of humidification. If it is not sufficiently limp it may be returned to the damp pack for another few minutes; otherwise it is removed (still between polyester web) and placed between dry blotters and pressing boards for drying/flattening (see Flattening/Tensioning/Drying).

This method can be adapted for use with multiple items by stacking up additional damp blotter, interleaving and parchment sandwiches in the pack. It is not suitable for severely distorted sheets which could crease under moderate weight or for leaves with significant media. (See Cains, 1982/83.)

Roll Pack: This method has been used in Record Offices of the U.K. and is described by Cains (1982/83). The object is placed between polyester web and then rolled in dampened fabric or blotters and placed in a sealed plastic tube or bag.

Trash Barrel: This technique is often used for oversized and rolled artifacts. A small plastic trash barrel is placed inside a larger barrel which is lined with damp blotters. The artifact, protected by polyester web, is placed in the center of the smaller trash barrel and then the top is covered with a tight-fitting lid. Metal barrels are not used to avoid the risk of metal contamination.

Moisture Chamber with Ultrasonic Humidifier Ultrasonic humidifiers generate a mist of very finely dispersed water droplets, in contrast with traditional humidification systems which expose artifacts only to water vapor. Therefore this system is a bit more hazardous to very water-sensitive media and mold-damaged skins. There is also an increased danger of condensation on the surface of the artifact, and on the interior of the chamber, where it could eventually condense and drip onto the surface of the item. Ultrasonic humidification does, however, quickly and conveniently produce a humid environment in a chamber, and is a popular method for humidifying a wide variety of materials, including parchment. (See Weidner 1985.) Museum Services Corporation will, in the near future, be marketing a new version of Marilyn Weidner's humidity chamber.

Ultrasonic mist is introduced into a chamber, such as a suction table dome or a covered sink. Some conservators let mist fill the enclosure and then place the objects in the chamber. Others prefer to place the objects in the chamber and then introduce the moisture. A good moisture chamber can be constructed by the conservator, as elaborate as the available tools and skills permit. Polyethylene can be draped over a deep sink or simple wood framework for a very simple chamber.

Enclosed Rack: A free-standing drying rack (often a modified Baker's rack) can be used as a mass treatment chamber for humidification of parchment items. The rack is enclosed with polyethylene sheeting. For access during use the polyethylene is draped in such a way as to create a curtain door. To prevent moisture from escaping at the base of the rack chains or book snakes are used to hold the sheeting against the floor. An ultrasonic humidifier and hose attachment is used to introduce moisture an any desired point. One common method is to set the humidifier up outside the chamber (for control and refill convenience) with the hose inserted at the top of the rack. A small fan placed inside near the point of moisture entry will help speed distribution. As in other humidification techniques, the parchment is sandwiched between interleaving before being placed on the rack.

A collapsible clothes line draped in polyethy-lene sheeting is sometimes used for folded sheets, such as book pages, that can be draped over the lines.

Lauscaux Chamber: The Lascaux chamber developed and described by Olivier Masson, which is available commercially from Lascaux Restauro, incorporates ultrasonic humidification. A desired humidity level can be achieved and maintained over long periods by means of an external humidistat.

Moisture Chamber Using Steam and/or Ultrasonic Mist

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Clarkson Conditioning Chamber: Christopher Clarkson has designed a system which performs three functions: 1) humidification, 2) drying by drawing air over a refrigeration system, and 3) introduces heat if required. The moisture is provided by one of two methods: by steam which is cooled before it enters the chamber or by ultrasonic transducer which is a plug in unit added to the chamber. Both are controlled by a humidistat. This system allows a great deal of control. It has sufficient capacity for numerous objects to be humidified simultaneously, and direct observation of the objects is possible. The objects can be held in a relaxed steady-state while awaiting tensioning and drying. (See Clarkson 1982.) This chamber is not commercially available.

Hotpack Humidity Test Chamber: The Hotpack Humidity Test Chamber is a commercially available chamber which is made by the Hotpack Corporation (Philadelphia, PA). It is currently used at the New York Public Library for the humidifi-cation of parchment documents and bookbindings. The moisture source is steam from an external vapor chamber which is connected to a water supply.

Applications of Alcohol and Water

(See Potential Alteration/Damage to Object in Treatment: Problems Caused by the Use of Organic Solvents.)

Immersion: Alcohol or alcohol and water baths have been used for separation of multiple blocked pages or sheets which cannot be pried apart (i.e. dry flood damaged material covered with mud.) The alcohol penetrated the skin and mud and reportedly resulted in even relaxation. (Giuffrida 1983.)

The advantages of this approach must be weighed against the hazards of solvent use. This is a drastic method which should probably be reserved as a last resort.

Spray Application: Some conservators have used spray application of 60/40 ethanol/water to achieve quick humidifi-cation/relaxation of parchment. This is not a gradual technique and it may not hydrate evenly. It might be resorted to in field situations for quick relaxation and inspection of distorted archaeological specimens where time and equipment are limited. It can also be useful for prolonging the relaxed state of parchment which has first been humidified in a chamber, but which requires prolonged manipulation and incremental local flattening. (See Local Treatment.) When this sort of flattening is laborious and time-consuming the conservator may not wish to return the artifact to the humidity chamber when it is almost dry but only partly flattened, possibly undoing the improvement that has already been gained. (Dreibholz 1983.)

Sometimes tensioning a parchment that is severely distorted or over-sized may also turn out to be a lengthy procedure. This is another case when spray application of alcohol/water may be needed to prolong working time, especially if the conservator is working in a dry environment. Spray application would not be appropriate for a napped surface or on vulnerable media. The use of alcohol solutions does entail the risk of dehydrating the skin and perhaps causing structural damage, so it must be used moderately and carefully.

Hazards

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The nature of parchment is due in part to its method of manufacture, see History of Manufacture and Use of Parchment. The parallel orientation of the fiber bundles that takes place during manufacture (by drying the skin under tension) makes parchment especially vulnerable when exposed to moisture. If left too long in the humidified state the fibers begin to realign themselves causing permanent and often radical planar alterations. Skin humidified too long can also become so soft that any tensioning can cause over stretching, deformation, and other unacceptable dimensional changes. Permanent damage may also occur if parchment is dried improperly. These hazards are noted in the various drying techniques described in Flattening/Tensioning/Drying. However, there are damages which can occur during humidification and before drying.

If a skin becomes too wet, it can become irreversibly translucent in areas, and if it is seriously degraded, as in the case of mold-damaged skin, degraded areas can gelatinize. Overly wet skin can become translucent under the pressure of a damp pack, as well as when pressed for drying. Skin left in the humidified state too long is susceptible to mold attack.

In enclosed chambers with standing water, steam, and/or ultrasonic mist condensation can occur both on the artifact and on the interior surfaces of the chamber where it can condense and drip onto the artifact, causing permanent damage to skins, media, and surface preparations.

Paint layers and other media may be softened by humidification, and these media can offset when they are in contact with blotters, screens, polyester web, and the like in humidification sandwiches and damp packs. Binder layers beneath paints can expand causing media to crack or flake, and flaking media can dislodge. (See Clarkson 1992.) Faint markings which contain bibliographic or paleographic information can be lost, and surface preparations involving glazes, grounds, and pumicing can be altered.

Some thin skins have a tendency to curl when they are humidified, and this can disturb sensitive media and surface preparations, and can cause tears in weak areas to lengthen. The tendency to curl may be so persistent that it is problematic to place the item under any restraint or weight without pressing curled-in areas.

All materials such as blotters, screens, and protective sheeting which come in contact with parchment under humidification should be clean and free of mold and metal (other than stainless steel) to avoid contamination.

Jordan (2011) and FitzGerald (2018) documented the use of magnets on parchment without clips, instead placing the magnets directly on the parchment to direct tension locally.

Local Treatment of Folds, Creases, Pleats

(See above)

One of the most direct ways to locally humidify a fold, crease or pleat is to apply a solution of either 50/50 water/ethanol or pure ethanol or isopropanol along the crease or fold line. However it is possible that tidelines may develop in discolored skins. In addition, some surface preparations (especially highly napped parchments) and coatings may be disturbed by the direct application of water or solvents. In these cases one can try more indirect methods of local humidification such as small squares of polyester web, Gore-Tex and damp blotter over the area to be relaxed and flattened. An ultrasonic humidifier with a hose attachment can also be useful for local humidification of a small area. The “Preservation Pencil,” sold by University Products, comes equipped with a plastic nozzle that fits on the end of the hose. For an even finer jet of ultrasonic mist one can attach a glass eye dropper or pipet to the end of the hose with some modifications. One must be extremely careful when using an ultrasonic humidifier in this way, however, because condensation will gradually build up at the end of the nozzle and drops of water may ultimately fall on the object. In order to prevent this from happening place the humidifier on the floor so that the condensation is able to drain back into the tank. On a regular basis, vigorously shake the nozzle off to the side of the work area, in order to expel any water droplets that have collected at the tip. One can also touch the end of the nozzle to a blotter every so often to wick up any free water that might have collected at the tip.

The local treatment of pleats in a parchment artifact may not always be advisable, depending on how the pleats have formed in the skin. If they are obviously the result of some type of mechanical damage or manipulation of the object (Clarkson 1992, Figs. 54a & 54b), they can usually be locally humidified and flattened out with a certain amount of success. If, however, the pleats have formed as a result of the expansion and contraction of certain areas of the skin, with changes in the surrounding environment, they may be much more difficult to remove. These types of pleats, which are seen more frequently in full thickness (i.e. unsplit) parchments than in modern split skins, are often associated with a type of cockling that is oriented parallel to the spine direction of the animal (Clarkson, 1992, Figs. 11, 25, & 26). When these pleats are located in the blank margins of an artifact, and do not extend into heavily painted areas, they can sometimes be locally humidified and dried under tension by an experienced conservator (Lee 1992, p.48). However, the manipulation of pleats in illuminated or heavily gilt areas could easily disturb the paint or gold nearby, so it is usually best not to attempt any form of local treatment in these situations (Lee 1992, p.47 and Figs. 4 & 6).

Humidification References | top

Flattening

The process of drying parchment is often conjoined with the humidification step, which together are referred to as “humidification and flattening.” Parchment should never be dried without restraint; doing so risks reintroducing cockling, shrinkage, or other deformation. Because parchment is formed (or deformed) by drying skin under tension, humidified parchment that is allowed to dry without restraint may attempt to reform its original animal shape. Even parchment that is “dry” will begin to lift and curl at the edges in humid environments, hence the advice to keep areas of parchment not being treated under wool felt to act as a mild restraint. For dry parchment, that is sufficient. Wet parchment requires more force.

Many factors determine the choice of technique for drying a humidified parchment artifact, including (but not limited to) the weakness of deteriorated or mold-damaged skin, the presence of tears or losses, soft or fragile media, the presence of seals and other attachments, the quantity of material being treated, and the techniques at which the conservator is practiced. Every technique of drying is more successful when sensitivity and experience are employed in carrying it out, and when the procedure is carefully monitored so that the conservator can respond quickly and alter the process if a problem arises. Unfortunately, this type of intuition is only acquired through practice.

The techniques discussed below need not be used in isolation or in their pure form. Approaches to flattening can be modified or combined to suit each individual problem, such as placing thick felts in a press when an object needs increased restraint but its surface or media need extra protection. Flattening under pressure can also be combined with tensioning techniques. However, all these techniques should be done to humidified parchment (local or overall); attempting to flatten dry parchment may result in more damage.

No matter how long a parchment is left restrained, it is not likely to remain completely flat for long once restraints are removed. The skin will most likely reassume a natural undulation, especially when exposed to humidity fluctuations (see Unique Qualities of Parchment as a Support). This must be accounted for in housing and storage of the artifact (see Housing).

It is generally not recommended to take apart, unlace, unfold, or detach attachments from documents for the sake of flattening. Some part or parts of the attachment may be too fragile to survive disassembly, and after the changes undergone by parchment in humidification and flattening, it may be impossible to put things back exactly as they were after the object has dried.

Drying Under Tension

The following techniques rely on adjustable padded clips attached to parchment edges and pulled to make the parchment taught so as to flatten it. For maximum control during the drying process, one should set up for tensioning before humidification begins so tensioning can be carried out at precisely the stage of humidification which the conservator thinks is optimal. The clips should be laid out on the board roughly in the shape of the artifact. They should all be laid with the same side down so that they will all pull at the edge of the parchment at the same angle. Position the pins to be easily accessible.

When the humidified artifact is laid on the board it is essential to work quickly so that it can be effectively tensioned before it starts to dry out. To this end it may be preferable to work with a colleague at opposite sides of the board, especially if the tensioning is tricky due to tears or an irregular shape, or if the item is over-sized. In such a situation some conservators are accustomed to replenishing the moisture in the artifact at intervals while they work, using an ultrasonic humidifier with a hose/nozzle attachment or a dahlia sprayer filled with a water/alcohol solution. One must be careful, however, not to apply moisture directly to an object that has sensitive media or surface preparations. For these objects is it better to raise the overall humidity in the room in order to prevent too rapid drying of the parchment and to permit a longer working time. In any case, tensioning should not be undertaken when the relative humidity is less than 50%, to avoid placing undue stress on the object as it dries out. One may also build a temporary plastic tent to work in if modifying the humidity in the entire work space is not possible.

Most conservators work from the centers out toward the corners, placing pairs of clips opposite each other in order to keep the tension as even as possible. The amount of stress created between each pair of clips can be judged both visually and by feeling the tension between the clips with the fingers. It is more important to get the entire sheet pinned out quickly than to lose drying time comparing each pair of clips as they are secured. After the sheet is pinned out one can inspect the entire sheet and again test the tautness of each clip, making adjustments as necessary. Ruling or written lines compared to a straight edge can be used to help with evaluation of evenness of tension.

Sometimes local deformations in a sheet can be improved by placing them under slightly more tension during pinning out, or by only humidifying that area and applying clips to that area while holding the rest of the document down with weight.

The whole tensioning process requires careful attentiveness, since the final shape and conformation of the artifact is determined by the manipulations of the conservator. Parchment should not be over-tensioned to the point that it is drum-tight. The moisture content of the skin can be checked during drying by gently touching its surface with the back of the fingers. The coolness of the parchment gradually decreases as it dries. If distortions should appear or existing distortions should worsen, the pins can be adjusted once more, or the parchment can be unclipped and returned to the humidity chamber while the conservator's treatment plan is reconsidered. If no problems arise, after a brief interval (5 minutes or so) all the clips can be moved a slight distance along the edge of the sheet in order to reduce the danger of leaving permanent damp marks in the edges. The clips should not be moved more than once to avoid disturbing the drying process.

When the object is nearly dry (time under tension depends on the thickness of the artifact and environmental conditions in the laboratory; the skin should be still slightly cool to the touch), it is usually unclipped quickly from the board and placed under felts with a board and weight for final drying. Blotters can also be used instead of felts but have the disadvantage of being much harder than felt and can reduce the natural undulations that occur in parchment documents (it was once fashionable to remove those undulations completely). Parchment should be should be left weighted for at least a week or preferably longer to ensure complete drying. Felts may be changed after one day and then left as is; blotters may need changing more rapidly. Drying under overall pressure also reduces clip marks and any other deformations.

Parchment may be so permanently and severely deformed that it can only be partially flattened using local humidification combined with tensioning. These distorted objects can, after tension drying, be padded with pieces of felt or softer material such as polyester or cotton batting for placement under felts and light weights.

Clips and Magnets

Text.

Jordan

Clips and Pins on a Board

A soft insulation board such as Homosote or a thick block of Ethafoam, will allow for a certain amount of movement in the pins as the skin begins to contract and dry under tension. In order to introduce a greater amount of flexibility into the system it is common to attach rubber bands to the handle of each bulldog clip and hook the ends around the pins that are stuck into the board. Use pins that are thick enough not to bend and have a handle for easy maneuvering. Alternatively, the pins can be made by hand using number 15 bookbinders sewing needles and short lengths of 1/2" thick wooden dowel (Cains 1982/83, 21).

The clips are first attached to all sides of the sheet starting at the corners. It is important to keep the jaws of the clips level with each other along each edge to avoid creating clip marks. An unclipped gap will be left over at the end of each side. A small gap will permit easy repositioning of the clips later on (for reducing clip marks); if the gap seems large enough to interfere with even tensioning then the other clips on that side can be slightly spaced to fill in the end. Ideally no gaps are left between the clips in order to avoid uneven tensioning.

When using plywood the clips are tensioned by stretching out the attached rubber bands with moderate tension and then inserting dissecting needles through the loop. In the other system employing a soft board the pins are placed directly through the lower hole in the clip handles. The needles are positioned at an angle, away from the center of the board, so that they will hold the clip firmly and not be pulled out as the parchment starts to contract.

Weighting the Edges

This technique is less frequently used than tensioning with bulldog clips (see below), and does not lend itself as well to local adjustment/manipulation of the sheet as the latter technique, but it works well for artifacts with straight, regular edges. It may be especially practical for oversized sheets which are too large to place on a stretching board, and composite oversized sheets (larger sheets composed of smaller sheets which are attached to each other end-to-end) where the separate sections can be humidified with Gore-Tex and weighted at the edges and dried one at a time.

Working through a protective barrier sheet such as spun bonded polyester the humidified piece or section can be pulled flat or smoothed by hand. Strips of spun-bonded polyester are laid over the edges, followed by blotter strips, then flat metal rulers or Plexiglas strips, and finally as many small weights as are felt to be necessary to provide the appropriate amount of pressure at the edges. Choosing the correct amount of weight is perhaps the most critical aspect of this procedure: too little weight will allow the parchment to slip from underneath as it contracts and dry unrestrained, and too much weight can cause marking, transparency, or damage to media at the edges.

Refer also to Barbara Giuffrida's description of hand manipulation and local weighting (Giuffrida 1983 pp.35–36) as there is a difference of opinion in such working practices.

Clips and Hanging Weights

In this system bulldog clips are attached to the edges of the artifact and tension is provided by small hanging weights that are suspended by strings from the “handles” of the clips. The principle of this method is that the humidified skin is held under light tension by the hanging weights. As the skin dries and contracts the clips remain firmly attached to the edges while the weights are free to move in response to the drying parchment. One of the difficulties, however, is in achieving equal tension around the perimeter of the artifact. (Giuffrida 1983 p.34) Douglas Cockerell's technique was to support the object using a free-standing wooden frame on which strings are tensioned in either direction, making a grid-like pattern. (Cockerell, 1938, p.84 and Fig. 23) Once the parchment was humidified the clips were attached to the edges of the object and the small lead fishing weights were suspended from the clips by strings, over the edges of the stretching frame. Wächter (1982, p.168) describes the use of a board to support the object during the tensioning process. The board is somewhat larger than the object all around and must be set up in such a way that the weights can hang freely from the clips, around all four edges of the parchment.

Clips and a Rigid Frame

This technique is derived from the method used in the manufacture of parchment, whereby the damp skin is tensioned on a rigid frame to dry. Giuffrida (Giuffrida 1983, pp.33–34) describes an Italian method that utilizes a circular hoop fitted with stainless steel clips and violin pegs. The clips are attached to the edges of the artifact while the violin pegs, which are connected to the clips by lengths of cord, are secured at 5 mm intervals around the circular frame. Adjustment of the tension on the skin is done with the violin pegs. Otto Wächter later perfected this technique by replacing the cord with chains, which could easily be adjusted in length according to the size of the object being tensioned. (Wächter, 1982, pp. 167–168) One of the main advantages of this system is that, because the frames can be positioned vertically, it is possible to view the object from both sides during the drying process. (Giuffrida, p.34) A more recent modification of this technique was developed by Smith and Bunting (see Nineteenth Century Fine Art Prints on Parchment). They use a stretching frame similar to that designed by Cockerell (see above) which consists of a wooden strainer with fishing line tensioned across in a grid pattern. In this case, however, the nails that hold the nylon line around the perimeter of the frame also act as rigid points against which the skin is tensioned. Rubber bands, instead of lengths of cord or chain, allow for more flexibility in the attachment of the bulldog clips to the object.

Accommodation of Attachments

Many attachments do not interfere with or influence the tensioning/drying process. Some seals, however, which are attached to the surface with water-sensitive adhesives could pop off during drying and would have to be reattached after the artifact is dry. Pendant seals that are laced in close to the edge may interfere with the placement of clips. When objects with unusual shapes or irregular edges are tensioned the process is still the same for the most part, although not all the clamps will extend at right angles from the edges of the artifact. By observing the surface of the item during pinning out it should become apparent which arrangement of clips will achieve the most level surface possible.

Hazards

Tensioning of parchment is not without its hazards. Improper tensioning can cause distortion of the plane or the shape of an artifact. Excessive tensioning, especially in combination with excessive humidification, can permanently increase the dimensions of an object (overall), cause tears in weak areas, or enlarge existing tears if they are not adequately secured beforehand. The clips can damage softened media. In addition, the following problems can occur when using some of the tension-drying methods described above.

Splits, Tears and Weak Areas: Tensioning is riskier, or at least more complicated, when a sheet is weak or torn. These areas should be watched closely to avoid over-tensioning during the pinning out and drying process (See Local Treatment: Tensioning at the Edge). Weak or torn areas should be mended or reinforced before humidification and flattening. The mends which are applied can be temporary, to be removed immediately after tensioning is completed, or permanent, if applied to areas which will ultimately need reinforcement. If the mends are meant to be temporary, they do not need to be aesthetically appropriate. They need only be strong enough to withstand the stress they will be placed under during tensioning. If they are temporary, the mends should be removed before placing the parchment under pressure, after tension drying is completed.

Transparency Caused by Excessive Moisture and Tension: Depending on the degree of moisture in the skin, and the type of weights used in this method of tensioning, it is possible to create transparent areas in the skin. In order to avoid this problem it is important not to overly humidify the skin and to use relatively light weights for the tensioning process.

Clip Marks and Distortions: There is always the danger of leaving clip marks and distortions at the edges yet they can usually be dealt with in the following ways. The modification of the bulldog clips can be improved by adding more cushioning and by making sure that the jaws of each clip are parallel to each other (see Unique Qualities of Parchment as a Support: Structural Qualities: Physical and Chemical Stability). The clips should be repositioned during drying (see above). Distortions and scalloping at the edges can be alleviated by making sure that the jaws of the clips are level with each other along each edge, and by not leaving gaps between clips. Isopropyl alcohol or alcohol/water can be applied locally to the marks during repositioning and/or prior to weighting. Also, a final local humidification and flattening can remove clip marks.

Pressing, or Drying Under Pressure

The simplest method of flattening parchment is to, after humidification, dry it under felt or blotter, a stiff board, and weight. The technique is commonly used after both local and overall humidification. While some conservators have a preference for drying under tension, pressing is usually best for parchment objects that are too delicate for tensioning, such as mold damaged or especially thin parchment where applying too much pressure can cause deformation, tears, or translucency. In all cases, when pressing take care to avoid creasing the parchment in looser and more naturally deformed areas such as the sides of the animal.

A frequent complication is the presence of seals, ties, ribbons, and other attachments, as well as platemarks and embossings and the folded-over borders seen in many legal documents. Usually accommodations can be made in simple ways. Pendant seals and ribbons can often be allowed to protrude (with support from below) from the press during drying. Cut-outs can be made in the blotters or felts used for pressing to allow for the extra thickness of attachments on the surface. Insert non-woven polyester under fold-overs and beneath loose flaps of surface attachments to avoid unintentionally adhering parts together during pressing.

Pressing Between Felts

Thick wool felts are often ideal for flattening parchment because they can keep an item under pressure while providing a thick interlayer with more cushioning than blotters. They allow moisture to pass through, promoting slow even drying. They do not cockle like blotters when they are damp, and therefore do not have to be changed at intervals which is both more convenient and more environmentally friendly. When more weight is desired, the felt can be doubled or tripled. The felt pile should be covered with a pressing board, and depending on the parchment, some additional light weight. Wool felts are light and impressionable enough to protect vulnerable media from crushing or flattening, especially illuminated leaves with raised gold leaf. A mold-damaged document can be safely pressed under felts alone when flattening with weight or in a press would be out of the question. If a skin has ragged edges or damages that might snag on the fibers of a felt, it can be sandwiched between pieces of tightly-spun polyester such as Holly-Tex cut larger than the object.

Pressing Between Blotters

Blotters are stiffer and harder than felts and will therefore produce flatter parchment. If the goal of flattening is to retain the natural undulations often exhibited in parchment, this technique may not be appropriate. The artifact should be placed between clean smooth pieces of polyester web such as Holly-Tex to prevent bonding of the parchment to the blotter, to prevent offsetting of media, and to avoid imparting the blotter texture or fibers to the surface of the parchment. A board, sheet of Plexiglas, or plate glass may be used for pressing with blotter. If needed, additional weight can be added to discourage cockling of the blotters. Blotter changes occur rapidly at first, and should be changed quickly so that the still partially humidified parchment will not begin to dry without restraint. When the blotters are no longer cockled by exposure to the parchment, the item should be left under weight for a week or preferably much longer. The first 2–4 days the blotters should be changed daily.

Standing Presses

[Editor's note: this technique is overkill and will likely result in parchment that is "too flat."] Parchment is sometimes flattened in a variety of presses, such as standing or nipping presses. These presses are capable of extremely high pressures that are potentially very dangerous to parchment. However, when used with experience and sensitivity, they can be a useful tool, capable of precise amounts of pressure. The humidified object is sandwiched between polyester web, felts or blotter, and pressing boards. The sandwich is centered in the press and the flywheel is turned until the point that only platen pressure is exerted. It is unwise to increase the pressure beyond this point. Only moderate pressure is needed for flattening parchment. Remember to check the parchment after a minute or so to make certain that there are no creases or folded-under edges.

Suction Table

Flattening parchment on a vacuum suction table provides even support under the piece at all times, critical when handling fragile, damaged parchment. It can be easier to obtain successful results without causing planar distortions, clip marks, or tearing of fragile and weak artifacts.

First, the parchment is humidified overall. Since the suction table is part of this treatment, humidification using a dome and ultrasonic humidifier on the suction table with the suction turned off can be a convenient option. After humidification, the suction table is prepared with a thick piece of blotter covered with a piece of polyester web. To close off the airflow, the perimeter of the suction table is covered with a silicone rubber membrane or polyester film. The conservator lays the parchment on the blotter. The parchment is carefully manipulated, usually from the center outward, to pull creases and distortions into plane and to close splits and tears. Low suction will provide more working time and is appropriate for medium to thin skins; higher suction may be necessary for thicker skins. Parts of the parchment can be protected from the suction until the conservator is ready to deal with them by placing a piece of plastic sheeting under the area. A plastic ruler can be used as a guide to ensure lines of text are straight. As the skin is manipulated into plane, the edges are covered with strips of Mylar to hold them down and prevent curling. The working time, rate, and evenness of drying can be adjusted by working inside a dome with an ultrasonic humidifier to provide the desired level of overall humidity. Areas of the parchment can be covered with plastic to slow drying, especially when there are joins or areas of the skin that vary significantly in thickness. A hose attached to an ultrasonic humidifier can be used to provide moisture locally as necessary. The drawing out of distortions usually only takes a minute or two.

As the flattening progresses, the conservator turns up the suction to the maximum setting. As with other humidification/flattening processes, the drying begins as soon as moisture ceases to be applied to the parchment. After the distortions have been worked out, the parchment is covered with a dry sheet of Gore-Tex (slick Teflon side in contact with the object), which provides an even overall restraint for the parchment as it gradually dries on the table. The Gore-Tex material is an excellent filter and will inhibit any impurities in the air that might otherwise be pulled into the parchment surface. After five to ten minutes, uncover the parchment and turn the skin over; it will have stabilized by this time but will not be fully dried. Recover with Gore-Tex and continue to dry for another ten to twenty minutes until mostly dry. Then move to the drying felt stack.

The hazards are similar to those encountered in flattening distorted paper objects on the vacuum suction table. Distortions can collapse into creases if the initial suction is too great, manipulation can cause tears, stretching and additional damage to the support. Water-damaged parchment documents that have gone translucent cannot be made more opaque on the suction table as is sometimes possible with tension drying. Parchment should never be completely dried on the vacuum suction table. If the parchment is left to dry on the suction table on one side only, when it is removed it may have a tendency to curl and this situation can be difficult to rectify.

Some conservators feel that, for media that has become softened during the humidification process, the quick application of warm dry air (delivered by a hair dryer) can be used to prevent off-setting on to the polyester web or Gore-Tex by hardening softened media. This should be done with care to prevent any drying of the parchment's surface. However, the possibility exists that the softened binder (usually gum or glaire) will shrink and ultimately crack in reaction. Manipulation can also damage sensitive and softened media. Softened thickly applied paint layers can be offset onto interleaving. Raised gesso may be flattened.

Stretch Drying

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This method of drying was originally developed in Europe but it is unclear how frequently this method is used now. A large sheet of Plexiglas is roughened slightly so as to adhere better to the terylene. A piece of terylene cloth with a smooth surface is then pasted to the Plexiglas and an additional coating of paste is applied on top of the fabric. The parchment artifact is humidified and then smoothed out on to the terylene, while the paste is still moist. Although flour paste is typically used for this step it often leaves a rough greyish film on the parchment surface. In order to avoid this unpleasant residue parchment size has been recommended as a substitute. (Giuffrida 1983 p.36)

Shrunken Areas

Parchment artifacts that have been damaged by water or heat are often horny and shrunken in certain areas - usually around the edges that were most exposed. (These areas often have a translucent appearance as well, especially when the damage has been caused by water.) If this type of object is humidified overall the rate of water absorption and the resulting relaxation of the skin can be very uneven, with the undamaged areas taking up moisture more rapidly than the horny, shrunken areas. This can lead to several problems, especially if the conservator prolongs the humidification process in order to relax and flatten out the damaged areas of the skin. In these situations it is sometimes better to treat horny or shrunken areas locally, either prior to or instead of overall humidification and flattening. Moisture can be introduced locally, using some of the methods described above, and the area can then be gently manipulated with the fingers and dried under pressure using small squares of polyester web, blotters or felts, Plexiglas and weights. If moisture alone is insufficient in relaxing the damaged area one can locally apply ethanol or isopropanol, either alone or in combination with water, by brush or spray or with a dampened blotter pack. Although methanol has been successfully used in the past as a softening agent for parchment it is extremely toxic and therefore no longer recommended. Other lubricants, such as urea and polyethelyene glycol (PEG), have been found to alter the character of parchment in a variety of ways and are also not recommended for current use (see Lubricants and Lubrication of Horny, Desiccated Parchment for further information on Lubricants and Lubrication.)

Repeat Humidification and Flattening

Sometimes a difficult flattening/tensioning problem can be solved by either repeating the same procedure after rehumidification of the object, gaining incremental improvement of the results with each repetition, or by using different approaches successively, such as local treatment followed by tensioning followed by pressing under weight. Barbara Giuffrida was able to flatten a badly damaged manuscript by easing out the skin with her hands and then placing small pieces of plexi and light weights on the outer perimeter of the sheet. The object was allowed to air dry under tension and it was then rehumidified and the tensioning process was repeated until most of the deformation had been removed from the skin. (NS) A similar process using gradual tensioning involves clipping and pinning out a humidified skin on a piece of soft board, yet one must be careful in the beginning not to put too much tension on very distorted areas. These distortions can often be worked out of the skin if it is dried under light tension and then humidified and tensioned again for a second or third time. In certain cases however, when the distortions are related to naturally loose areas in the skin (such as the axilla) rather than to damage by water or heat, it can be extremely difficult to achieve a flat planar appearance.

Move this:

Accommodation of Joined/Multiple Sheets

It is possible to dry and flatten joined parchment sheets using a tensioning method (Burns and Bignell 1993). Multiple sheets are often legal documents which were joined using official seals or a lacing system designed to prevent tampering. Many of these systems can not be undone without doing permanent damage to these auxiliary materials or to the area of overlap with the sheets. Where the sheets are joined with cords, threads, or ribbons the condition of these materials must also be considered. It may be preferable to settle for a document that is "flat enough" and still maintains its original configuration. If a multiple-sheet document is pressed as a unit, the amount of humidification and pressure it is exposed to should be very moderate, and a thin non-stick material such as smooth spun-bonded polyester should be inserted between all sheets to prevent their sticking together.

Sometimes the top sheet of a multiple-sheet document may be more cockled than the successive sheets, and the treatment goal may be to increase the flatness of just that sheet. In that case the sheet can be humidified while remaining attached using Gore-Tex and blotters or any other system for local humidification (see Humidification and Local Treatment) and isolating it from the sheets underneath using polyester film. Similar techniques have been used for parchment book pages that remain in the binding. The document can then be weighted under felts, or the single sheet can be dried under tension (see below). It is also possible, with careful planning and dexterity, to tension all of the multiple sheets at once (see Burns and Bignell 1994).

Flattening References | top

Repair and Filling Losses

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Watanabe 2017.

Parchment may require repairs when the membrane is torn, cut, has incurred insect damage, etc. With improper handling of the object, these damages may continue to grow in size or severity despite the relative strength of parchment. Unlike paper, the thickness of an animal skin can vary considerably. These variations, which may be more evident in a large piece of parchment, may be from natural differences between areas of a skin (i.e. neck and butt being thicker than the belly or axilla) or from the manufacturing process, such as uneven scraping. Therefore the thickness of mending material, the strength of the adhesive and weighting of the mend may also need to be adjusted for repair of tears and losses in different locations within a sheet.

A hole from the manufacturing process generally does not need repair unless the hole itself is torn.

Due to the strength and reactive nature of parchment it is often necessary to mend both sides of a tear or split.

[Edited from original BPG Parchment page]

Often when a break occurs in parchment, a gap widens more than one would expect in a paper sheet because of the alignment of the collagen fibers. Reaction of the skin to temperature and humidity can increase this widening. While humidification can sometimes correct distorted tears, it is often necessary to accept a wider gap when a tear is repaired because forcing the edges to meet will cause cockling throughout the sheet which can not be corrected.

Parchment requires a stronger adhesive than paper due to the presence of natural grease in the skin. The moisture content of water-based adhesives should be carefully controlled because of the hydroscopic nature of parchment. This may require using dryer, more viscous adhesives and drying the mend under weight with stricter attention to the amount and duration of the weighting. Excessive weight on a wet mend could conceivably introduce the hazards associated with excessive pressure during flattening. Inadequate weighting can lead to cockling of the skin and failure of the repair. A tacking iron must not be used to dry the adhesive of a mend because the heat of the iron will damage the parchment.

A seriously mold-damaged or otherwise disintegrated parchment may have lost so much of its integrity that it may respond only weakly to humidity fluctuations, and a weaker adhesive will be adequate. A too-strong adhesive can introduce tension into a weak skin that can lead to tearing. The surface may be so crumbly or powdery that a stronger adhesive may pull material from the surface of the parchment, creating a skinned area.

Specialty Materials

Goldbeater's skin and Fish skin

Transparent membranes such as goldbeater's skin and fish skin are usually employed for the repair of small tears and perforated areas in a parchment artifact that do not require a great deal of support. Although a variety of adhesives can be used for attaching the membrane gelatin or parchment size are most common. Natural membranes are particularly useful for overlaying damages in text or image areas because they are so transparent. However, some conservators find that these materials are too shiny when applied to parchments that have a very pronounced nap. Goldbeater's skin or fish skin can also be very useful in supporting a large parchment fill, especially when the loss occurs in an area of text or image. (See Mending and Filling: Combinations of Above: Parchment and Transparent Membrane.)

Since both goldbeater's skin and fish skin are very thin and reactive to aqueous adhesives the use of a temporary support can greatly facilitate the cutting out and attachment of the repair. Anthony Cains first introduced the technique of mounting transparent membrane to heat-set tissue as a temporary carrier. (See Mending, Filling and Lining Materials: Animal Membrane.) In this process the heat-set tissue is adhered in advance to a large piece of membrane. The repair patch is cut out using scissors, a scalpel or an architect's swivel knife. Adhesive is applied to the membrane, which is then positioned over the area of damage and gently pressed in place. The heat-set tissue can be released immediately after the repair is secured by simple peeling, if the adhesive has not cooled too much during the repair process, or by applying organic solvent (usually ethanol or acetone) to the tissue with a brush.

Several other techniques of temporarily supporting a mend of transparent membrane during the repair process are currently in use. One method employs polyester web which is attached to the membrane with Tylose MH300 (a cellulose ether) in advance and then dried under pressure. The patch is cut out of the laminate, adhesive is applied to the goldbeater's skin and the patch is adhered skin side down. Once the repair has dried in place the lining of polyester web is removed using moisture.(UB) Another technique uses a piece of light weight polyester film as the temporary support. The goldbeater's skin is pasted out on the polyester film and excess paste is wiped away from around the edges of the membrane. Holding the edges of the Mylar support the goldbeater's skin is positioned over the damaged area and pressed in place. The Mylar is peeled away and the repair is dried under pressure with polyester web and blotter.(DE)

Sausage Casing

Sausage casing is currently used in many large libraries and record offices in the U.K. (See Mending, Filling and Lining Materials: Reconstituted Collagen.) It is less expensive and more readily available than transparent animal membrane, and because it is made from a variety of materials including collagen, it does not react as strongly to moisture and is therefore easier to handle than the natural products. The use of sausage casing for the repair of parchment is described in detail by Giuffrida 1983, pp.30–31.

Among many present day conservators of parchment there are several objections to the use of sausage casing for repair. The material usually has a distinct yellow tone that makes it more visually apparent than goldbeater's or fish skin. It has a relatively poor tensile strength when compared to the natural membranes; with some products the strength of the material seems to decrease upon aging and it gradually becomes very brittle. The variety of methods of manufacture (natural casings, reconstituted collagen casings, non-edible sausage casings, thermoplastic casings, etc.) make it important to know how the casing under consideration was manufactured. (See Karmas 1973 for further information on the manufacture of sausage casing.)

Adhered Mends

A widely-accepted method of filling losses involves the use of new parchment. A loss is filled with material that is as similar as possible to the original so that the sheet and the fills will expand and contract uniformly in response to humidity fluctuations. Skin is chosen for the fill that is similar in thickness and appearance, from the same animal species, and if possible, conforming to the orientation and location of the skin on the original animal's body. There is certainly an aesthetic appeal to the preference for filling like materials with like. However, identifying the species of old parchment is sometimes extremely problematic. (Sometimes it can even be difficult to distinguish parchment from paper- see Identification of Parchment.) Also, there are numerous factors that influence the physical behavior of parchment. These include the age and physical condition of the animal, biological variations and breed differences within the species, and injuries, scars, bruises and other anomalies in a particular skin. Country of origin, age and extent of deterioration of the parchment artifact, the history of its storage and use, and innumerable variables in the method of manufacture are further influences on the character of parchment. Contemporary parchment manufacturers have thus far been unable to replicate the quality of ancient parchments, and ancient parchments in general respond very differently than modern ones to humidity fluctuations. Maria Cristina Berardi's 1993 study of parchment deformation Why Does Parchment Deform? Some Observations and Considerations (Berardi1992), concluded that the individuality of behavior of a particular parchment prevails over its species characteristics, and supported the use of Japanese paper as an alternative fill material.

Some practitioners advocate the use of a more generic parchment fill material which is dyed, trimmed, and thinned to suit each particular parchment artifact. Anthony Cains in his article Repair Treatments for Vellum Manuscripts (Cains 1982 or Cains 1987) describes the preparation and use of fetal calf parchment (i.e. slunk) for infilling. According to Cains, the fill should be thinner and more flexible than the original. If necessary the skin is taped to a glass and placed over a light box for thinning with a very sharp spoke-shave blade, always from the flesh side. Any other surface preparation can then be carried out, such as sanding or pouncing. The material can be toned a sympathetic color with aniline dyes, either by surface application or by immersion. (See Mending, Filling and Lining Materials: Parchment: Preparation: Toning for further information on toning parchment for repair.) It is best to carry out toning before beveling so that when the fill is inlaid the overlap will not create a dark border. Bevelling (“scarfing”) is done widely (3–5 mm.) so that the bonding surfaces are wide enough to ensure a firm attachment. Bevelling can be done using scalpels, knives, or flexible-shaft drills. Sanding sticks made by gluing fine sandpaper to wooden dowels can also be used. Generally only the infill is bevelled, never the original.

Some conservators do feel, however, that the original may be bevelled. Roger Powell always bevelled the original where possible. This was not done on Kells, though, because the custodians didn't want any original material removed (see Powell, 1956). Nicholas Pickwoad has often bevelled the original, believing it gives excellent visual results with great strength. This is only done where there is no text or decoration that would be removed or put at risk Multiple repairs that lie over each other in bound books can give serious problems with swelling without such scarfing (more a problem when using parchment for repair than paper). (NP)

Japanese Paper Repairs

Japanese paper is used by some conservators for mending tears and filling losses in flat parchment artifacts. Although Japanese paper is a material that is foreign to parchment, with dissimilar behavior and appearance, it can function well. The paper conservator used to repairing with Japanese paper may choose to repair a tear in his/her customary way (see Mending), but must take into consideration that a stronger and dryer adhesive is necessary in order to get the paper to stick As mentioned above, a tacking iron should not be used for drying the repair. The paper should be thinner and weaker than the parchment, so there is little danger of it straining or deforming the skin over time. For weak, degraded, or thin parchment, a thin paper may be the best mending choice, because any new parchment or animal membrane is likely to be too strong. A repair that is too strong can also skin the surface of a degraded parchment.

For thicker paper to fill losses, as many layers as desired can be laminated together. For the sake of appearance the paper fill should be thick enough to approximate the opacity of the original; it is not necessary for any functional reason for the fill to be as thick as the original. If the fill paper is laminated alternately crossing the grain, this and the presence of the adhesive will reduce the response of the infill to humidity fluctuations. It is true that such a non-responsive fill will not move in unison with the surrounding parchment, but if one accepts the difficulty of matching the movement of parchment fills to parchment artifacts (see Berardi 1993), one might settle for a fill which can at least be predicted not to move in conflict with the artifact.

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Paper mends and fills can be toned a sympathetic color using watercolor or acrylic paints (see Mending, Filling and Lining Materials: Japanese Paper: Preparation for further information on toning paper for repair). In order to imitate the surface appearance of parchment paper surfaces can be burnished (before inlaying) with a bone folder. Very good imitations of the appearance of those parchments that have a hard, smooth surface can be achieved by loading the surface of the fill paper with starch paste or PVA dispersion, drying, and burnishing the surface. SC6000 (an acrylic polymer and wax emulsion) has also been used to improve the appearance of a paper mend (see Mending, Filling and Lining Materials: Japanese Paper: Use). Japanese paper adhered with PVA dispersions mimic parchment very well in flexibility and texture. When toned with acrylics the repairs can be virtually indistinguishable from the original.

When adhering Japanese paper with PVA a medium viscosity seems to work best. If too thick, the adhesive is difficult to handle and doesn't seem to improve the transparency of the repair. If too thin, the Japanese paper doesn't become as transparent as with the thicker solutions. At the Folger Library, Klucel G in ethanol is used in combination with the PVA method, after applying the tissue to the parchment a coating of Klucel G is applied to the surface and the tissue is then rubbed down. As the mend progressively dries, further Klucel G is applied; this acts as a lubricant to the teflon folder being used and it seems to make the repair less visible, frequently negating any need to tone the paper afterwards. If inpainting is needed acrylics seems to work well. (Note this method of repair is suitable only for finished parchment surfaces; it is not intended for the soft nap surfaced parchments.)

False Margins

Western Paper

Many flat parchment artifacts have been infilled in the past using western paper. Often they are reasonably attractive in appearance, secure in attachment, and have not created any puckering or other deformity over many years. However, innumerable cases have also been seen where Western paper used to infill parchment has caused severe puckering and distortion. There are examples in the New York University's Conservation Program sample collection students. (JFM) Therefore, since current opinion diverges, the use of Western papers for repair should be carefully considered.

Heat-set Tissue

Library of Congress heat-set tissue can be used for simple repairs of parchment. It can also be used as a temporary repair during tensioning. This material is the only heat-set tissue which at this writing that has been thoroughly evaluated for archival stability. Both LC Heat-set and the leafcast Gossamer Tissue are commercially available. The chief difference in the use of these papers for parchment repair is that heat cannot be used to activate the adhesive due to potential damage to the parchment (see Potential Alteration/Damage to Object in Treatment: Problems Caused by Use of Heat). Instead the tissues are activated by wetting out with either ethanol or acetone depending on the nature of the adhesive and media, positioning the tissue, lightly burnishing through a protective layer of non-woven polyester web, and then weighting it to maintain contact until dry. This provides a mend that is unobtrusively translucent and may be suitable for areas where soluble media preclude the use of aqueous adhesive. The mend is not aggressively strong, but where increased strength is desired its light weight and translucency suits it for use on both sides of a skin. The Gossamer Tissue is often selected for its aesthetic qualities in lieu of animal membrane. When used for overlaying damaged areas of text or illumination (in particular to both sides of the piece) the tissue will provide support without the visual distraction (sheen) that other materials like fish skin and goldbeater's skin can have.

Heat-set Membrane

Heat-set adhesives can also be cast onto animal membranes such as goldbeater's skin, or even parchment which has been thinned, for unobtrusive mends which can also help hold degraded, crumbling surfaces of a skin together. Heat-set membranes are not commercially available, and have to be prepared in the conservation workshop. (See Cains, 1992.)

Combinations of Above

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Parchment and Transparent Membrane: Parchment is sometimes used in combination with animal membrane when large inserts require stronger adhesion to the original. By allowing the membrane to extend beyond the parchment fill, it provides an overlap which is secured with an appropriate adhesive to the borders of the loss. Alternatively, strips of membrane can be attached only to the borders of the parchment infill in order to secure it in place. Another technique which is described by Anthony Cains in Repair Techniques for Vellum Manuscripts (see Cains 1982 or Cains 1987) is to build up a three-layered stepped membrane flange in which the middle layer will fit inside the bevel of the new parchment and the outer membranes will extend beyond its edge. The infill can be secured in position with one overlapping membrane secured to the front of the artifact and one secured to the reverse. Using transparent membrane in this way should not obscure text that is overaid.

Japanese Paper and Membrane: Technique currently used by Nancy Southworth and Marnie Cobbs which uses gelatin to laminate Japanese paper and goldbeater's skin. They have also used Jade 403 to laminate Japanese paper and goldbeater's skin.

Wide Splits/Tears

Splits and tears in a parchment artifact may begin to close up once the skin is humidified overall. However, as the parchment contracts upon drying these areas of damage will open out again and may even tear further, depending on the drying method that is employed. For these reasons it is advisable to repair any splits and tears, in either a temporary or permanent way, before overall humidification and flattening of the artifact is carried out. If the split or tear is already well aligned, and requires no further manipulation, it is usually preferable to attach a permanent mend of transparent membrane, new parchment or paper to secure the area (see Mending and Filling for a more complete description of these methods). If, on the other hand, there is a wide gap in the split or tear or if the area is misaligned due to distortions in the skin, a temporary repair might be more suitable at this point. Depending upon the area in the skin where the damage has occurred, and the proximity of sensitive media, tears can sometimes be partially closed or realigned with the local introduction of moisture (see techniques described above) followed by hand manipulation and drying under light pressure. Before the area is very dry, however, the temporary repair is applied. This can consist of a piece of Japanese tissue applied with starch paste or an adhesive-coated tissue such as heat-set tissue which is activated with solvent. Pressure-sensitive tapes have been used by some conservators for the temporary repair of splits and tears (Cains 1982/83, p.17) yet there is always the risk of leaving some adhesive residue behind, especially if the skin has a prominent nap. For temporary repairs it is important to choose a relatively lightweight material which is very flexible and also easily removed at a later point. Therefore mends adhered with either gelatin or parchment size are usually not appropriate for this purpose.

At the Walters Art Gallery splits and tears in a badly mold-damaged parchment manuscript were recently humidified and temporarily repaired with the help of a book suction unit (described in Quandt 1992, pp.188–189). The first leaf of the manuscript was severely perforated and torn and many damaged areas were misaligned. The leaf was positioned on the suction table and then humidified overall under polyester web, Gore-Tex and damp blotters. Once the skin was sufficiently relaxed tears and splits were gradually realigned while the leaf was held in place under slight vaccuum pressure. Small pieces of a lightweight Japanese tissue, previously coated with a viscous solution of Klucel-J in ethanol, were positioned over the tears, moistened with ethanol, and pressed in place. Each patch of repair tissue was locally weighted, under squares of blotter and Plexiglas, as the work progressed across the leaf. Some tears and splits, which could not be completely closed or realigned during the initial stages of treatment, were rehumidified locally using Gore-Tex and damp blotters. The existing repairs were removed, the damaged areas were manipulated further and new temporary repairs were then applied. After all of the necessary work on the suction table had been completed the manuscript was removed and left under pressure for a couple of weeks, to allow the moisture content of the parchment to come to equilibrium. Temporary repair patches were gradually removed and the damaged areas were mended for a final time, using carefully profiled pieces of the same adhesive-coated tissue. (AQ)

Lining

Occasionally Asian paper is used to line weak parchment documents.

See BPG Parchment Historic Treatments and Materials > Lining and Laminating for methods no longer used.

Non-Aqueous Repairs

Cains (1992) and conservators at Trinity College Dublin (TCD) developed a technique for delicate or badly damaged parchment repair. Fish skin or swim bladder is coated with an acrylic resin that could be adhered or removed by reactivating the resin with solvent. Baldwin and Gillis (2006, 64) describe using this technique on a 13th-century Irish Biblia Sacra. However, Quandt (2021, footnote 40) reported that TCD stopped using the technique in 2008.

Sewn Repairs

Parchment makers utilized sewn repairs on ruptures in the skin that occurred during manufacture. Sewn repairs were also historically used on folios as an alternative to adhered parchment patches. While nearly always utilitarian in appearance, there are instances of elaborate and artistic “embroidered” repairs made by nuns.

Conservators use this type of repair rarely, only to satisfy specific visual or physical requirements of the object. The major drawback of the technique is that it requires puncturing a series of small holes in the skin, thus permanently altering the appearance and physical integrity of the folio and making it an option of last resort. Furthermore, the raised surface of the lacing and knotting can imprint or abrade the surfaces of adjoining leaves. However, it will only work where the area to be sewn is strong and healthy. (Some conservators have dealt with this problem by reinforcing the edges of the knife cut or tear with transparent membrane before sewing across the break.) A sewn repair might cause distortion or tearing if it hinders the natural movement of the parchment in response to humidity fluctuations.

The technique does have advantages. One can place the holes around the text and obscure less than using overlaid patches. Sewn repairs also allow the folio to experience a significant amount of flexing at the tear, which may be desirable in some circumstances. Sewing may be particularly appropriate for tears where there are no overlaps along the repair, as in a knife cut, or when the parchment must be stretched over a frame, such as in a work of art on parchment that is on an original strainer.

Sewn repairs are most commonly carried out with either linen thread or parchment strips. Some conservators prefer sewing with sinew. Descriptions of the technique and diagrams are given by Cains (1982/83) and Giuffrida (1983). The sewing material should be as fine in proportion as possible. Rather than use a needle, the thread end is stiffened (or the leading end of the parchment strip is tapered). The sewing material is pulled and lightly tensioned through pre-cut slits or holes (rounded holes may be less likely to tear out). They should be staggered for a less bulky repair, and a figure-eight sewing pattern is used so that the edges will butt and not overlap, which would also make the repair bulky. The “baseball” stitch is an alternative sewing pattern.

Sometimes original sewn repairs have missing or broken thread (although replacing this is usually only needed when the rupture occurs at the outer edge of the sheet). Thread may also need to be replaced in oversized or rolled artifacts where the individual sheets were originally joined by sewing.

[Powell Kells parchment folios sewn to meeting guards. CCM 8 historical sewn repairs]

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Pulp Fills

Several variations of the technique of pulp filling have been created and adapted for parchment.

Wouters et. al. 1990, 1992 and 1993 describe an aqueous suspension of purified hide powder prepared in 0.03% Tylose MH300. The slurry pipetted on to the humidified parchment on a suction table.

Laursen 1985 describes a technique using Hide Powder and Eukanol Glanz N where no water is involved in the application of the pulp, but the fill needs the additional support of a layer of goldbeater's skin and an aqueous adhesive is used for its attachment.

Margotieva and Bykova 1991 describe using parchment powder and a 5% solution of Ftorlon 26L in 1:1:1 ethyl acetate/butyl acetate/acetone to make a pulp.

Beothy-Kozocsa et. al. 1987 and 1990 describe using a wide variety of materials including hide powder, paper fiber, parchment size, hydroxyethylmethylcellulose, water, ethanol, isopropanol and a fungicide called Preventol CMK.

Consolidation of Degraded Parchment

Parchment that has been affected by mold is much more prone to damage from use due to the extreme weakening of the fiber structure. In addition, these areas can easily darken with the use of aqueous adhesives during the process of repair. Consolidation can usually help to strengthen weak and perforated areas of parchment and sometimes act as “sizing agents” by filling in the loose fiber structure. When the mold damage occurs in relatively small areas consolidation can be carried out locally using a brush. Otherwise it is necessary to apply the consolidant in spray form for the treatment of more extensive areas of mold damage. These and other techniques are described below. Small areas should be tested with any consolidant prior to use.)

Depending on the type of adhesive that is selected, and the way in which it is applied, the chances of altering the color and surface characteristics of the parchment are considerable especially if the degraded parchment is consolidated overall rather than locally. Consider also the ageing characteristics of the chosen adhesive and how it will react with the parchment support over time.

There are a number of materials that were popular in the 20^th century but are no longer in use due to their damaging effects, such as soluble nylon and gelatin baths. See Historical…

Cains (date) developed a local consolidation technique using a dilute solution of Klucel-G in ethanol which is applied to the area of degraded parchment with a brush.

The spray consolidation of a degraded parchment artifact can be aided in many ways by a suction table. The suction holds the object in place during treatment and allows for a more effective penetration of the consolidant into the skin. Cockling that would otherwise occur with the application of an aqueous consolidant is kept under control and the skin stays relatively dry and free of distortions as a result. Noticeable alteration of the color and surface characteristics of the skin, which could easily occur with the use of aqueous consolidants, is generally avoided when a suction table is employed. Two similar methods of spray consolidation have been described by Quandt (1986 and 1992) whereby flaking ink and/or mold damaged parchment were treated.

Stephan Michalski of the Canadian Conservation Institute.

Parchment Repair References | top

Extreme Parchment Conservation

Fire Damaged Parchment

Pal et al. 2016

Reid, Zoë and Benjamin van de Wetering. 2012. "Conservation of the sixteenth- and seventeenth-century Chancery pleadings at the National Archives of Ireland." Journal of the Institute of Conservation 35(2). DOI: 10.1080/19455224.2012.722779. Link to subscription journal.

Discusses a large-scale project to conserve 5265 fire-damage parchments. The treatment methods are well-described and broadly applicable. They include dry cleaning with soot sponges; damp-pack humidification; reshaping with pressure, tension, or suction; and repair with intestine leather, goldbeater’s skin, or goatskin, applied with warm gelatin. Introduces the use of a "stretching aid": two metal discs pressed together with a bolt and butterfly nut to hold together a loss or tear during reshaping.

de Guevara, Mariluz Beltran and Paul Garside. 2013. "The Conservation of the Burnt Cotton Collection." Journal Of The Institute Of Conservation 36 (2). DOI: 10.1080/19455224.2013.815122. Accessed May 5, 2017.

Describes a project at the British Library to preserve a collection of fire-damaged, bound parchment manuscripts from the 4th - 17th C.

Facchini, Alessandro, Carlo Malara, Giovanni Bazzani, and Pietro Luigi Cavallottiz. 2000. "Ancient Parchment Examination by Surface Investigation Methods." Journal of Colloid and Interface Science 231. DOI: 10.1006/jcis.2000.7138.

Before and after treatment analysis of a parchment manuscript damaged in a 1904 fire. The parchment was shrunken and the pages "bound by the adhesive substance coming from the collagen damage." The treatment consisted of humidification with water and alcohol vapor to soften the parchment and the adhesive, page separation, and stretch drying. The drying was sometimes preceded by immersion in "a hydroalcoholic solution of urea (2 wt%) and sodium chloride (2 wt%)" followed by a "50/50 wt% ethyl alcohol/water solution to improve the parchment elasticity." This article examines the parchment (as well as mock-ups) to evaluate the treatment results based on measuring surface characteristics like pore size distribution, water adsorption, SEM images, and microindentation. This article suggest that these are valid measurements for evaluating parchment treatments. There is not a clear distinction between samples that were humidified and stretched vs. samples that also received the urea, sodium chloride, and ethanol-water bath.

Quant, Abigail. 1996. "Recent Developments in the Conservation of Parchment Manuscripts." The Book and Paper Group Annual 15.

This article talks about successful treatment of a heat damaged parchment manuscript and the successful reversal of stiff and horny areas.

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Emergency Drying

Water in an emergency situation can cause stains and dimensional changes that will permanently disfigure parchment. If a saturated skin is allowed to dry unrestrained it will develop horny and translucent areas that usually are impossible to reverse later on. Media softened by moisture is prone to smearing and off-setting. Elevated temperatures and high humidity also create an environment that encourages mold activity, with mold growth occuring within 24–48 hours in these situations. For these reasons parchment should be dried as soon as possible if it is wet.

Parchment artifacts that are wet or very damp are extremely susceptible to mechanical damage and must be handled carefully. When removing them from a disaster scene they should be transported using an auxiliary support. In an emergency situation parchment should, if possible, be identified and segregated from paper and other materials. Where large quanti-ties of parchment are affected a separate area should be set up for triage of parchment, because its emergency treatment may be quite different from that appropriate for other types of material. Books with vellum pages or covers should be included in this grouping. Framed artifacts should be unframed as soon as possible, while remaining alert to the danger of adhesion of the skin or media to glazing. Some framed objects may be tensioned on strainers or drummed on to board. If allowed to air dry they are subject to severe warping and splitting as the skin contracts against the rigid support. Therefore controlled drying is especially important for these objects.

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The immediate goal of emergency treatment is to stabilize the artifact before any further damage occurs. In some situations heavy deposits of wet mud can be lightly blotted off or removed mechanically, but there is a risk that the media, surface preparation, or skin below the mud could be damaged in the process. Usually it is safer to remove dirt after the parchment has been dried. Water-damaged media may also be best treated after the artifact has been dried. Freeze drying and vacuum drying usually cause some dessication of the binder, leaving the media loose and powdery and in need of consolidation. After the water-damaged parchment has been dried rehumidification and controlled drying and flattening will often improve the dimensional characteristics of the skin and return it to plane.

The chosen method of drying will usually be determined by the number of artifacts that have been water damaged in a disaster. In most situations a large volume of material will require immediate attention and methods of mass treatment such as freezing and freeze drying are preferable. If, however, only a single artifact or a very small number of artifacts have been water damaged the conservator may consider some of the more standard methods used for drying parchment. For example, small quantities of damp parchment documents that are not seriously deformed and with media that are not vulnerable can be dried and flattened under light pressure between polyester web interleaving and thick blotters or blankets. (See Flattening/Tensioning/Drying) Parchment that is wet, however, must be pressed with extreme caution as its vulnerability to the hazards of excessive pressure are heightened. (See Potential Alteration/Damage to Object in Treatment.) Also, pressure on parchment can cause a heavy accretion such as mud to embed itself in the surface. Uneven wetness may also be a problem, causing localized cockling or swelling, and complicating drying procedures. Wet areas may also crease or turn translucent under pressure. In one case a single waterlogged parchment document was successfully dried on the suction table (Logan and Young 1987.) Unfortunately, in an emergency situation the time or the facilities for suction table drying are often not available.

Tensioning is very dangerous for wet parchment because of its weakened state and must not be used. (See Potential Alteration/Damage to Object in Treatment) Tensioning would also be inappropriate for partially wet parchment, as stretching would concentrate in the wet areas, causing local distortions. If none of the usual drying techniques are feasible in an emergency situation, then the parchment artifacts should be frozen. Freezing “converts the water to ice, halts distortion in position and arrests (but does not kill) mould growth. Freezing buys time to think, to respond sensibly to problems and to make unhuried decisions.” (Parker 1993, p.176.)

If time permits single parchment artifacts may be interleaved with freezer or waxed paper before they are placed in containers such as plastic milk crates to be frozen in groups. (The presence of holes in the crates allows for the passage of air during freezing. Crates or boxes with solid walls can slow up the freezing process by insulating the material inside, so these should not be used.) The crates should not be overfilled or there may be too much weight on top of wet artifacts at the bottom. As in any emergency situation, the contents of the crates should be identified and kept track of as best as possible. Books with vellum covers or leaves can be wrapped tightly to help prevent distortions from developing during freezing and subsequent drying. Bagging books in polyethylene or interleaving them with plastic before they are put into crates will help in later retrieval of the material. In some situations, it may be appropriate to remove vellum covers before freezing to avoid distortion of the text block and permit separate treatment or replacement of the cover material.

In the case of books with parchment leaves and media that are water-sensitive, strapping the volumes may increase the extent of offsetting of the media. At the British Library recent tests with a variety of freezing and freeze drying methods have shown that illuminated parchment must be handled in a particular way to avoid further damage to the media. During initial salvage of water-damaged material books that are already flat should be removed from water horizontally. If, however, the books are still standing on a shelf they should be transferred to a crate in an upright position “so that water will not flow onto fresh pigment, but will only move slowly by absorption due to the hygroscopic nature of vellum.” (Parker 1993, p.182.)

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After freezing there are four possible ways to dry parchment. The first is to thaw the parchment at room temperature in a closed humidity chamber. This conditioning may include a period of exposure to air-drying which stops short of allowing the parchment to dry out, followed by returning it to a humidity chamber. The advantage to this approach is that skin which is too wet or unevenly wet can be moderately and evenly humidified, so that one of the customary drying techniques can be employed. It also permits monitoring of water-sensitive media during drying.

Freezer drying, vacuum freeze drying, and vacuum thermal drying are three additional ways frozen material can be dried. All these techniques can be expected to result in some shrinkage and embrittlement of the parchment, although the embrittlement reportedly recedes as the parchment acclimatizes to moderate environmental conditions. Shrinkage can usually be remedied with rehumidification and controlled drying of the artifact. For some archival material, however, the shrinkage may be considered unimportant. These three techniques do not improve distortions, and can cause further dessication of media and adhesives.

Freeze-drying occurs if frozen material is left in a self-defrosting blast freezer long enough. (See Ogden/Buchanan 1992, for a description of all three freeze-drying processes). This method requires temperatures below -10 degrees F. and may take up to several months. Vacuum thermal drying dries material under vacuum above 32 degrees F. and is likely to cause additional distortion of parchment during the drying process. This distortion can be especially marked in the case of complex artifacts such as books and scrolls. Vacuum freeze drying is carried out below 32 degrees F. and is not supposed to create any new swelling or distortion while it dries by sublimation of the ice content.

Bog Parchment

Irish conservator John Gillis has written extensively about his experience conserving the Fadden More Psalter. In addition, Oliver Fallon (2019) made a documentary (available on YouTube) about the discovery and conservation of Fadden More.

Disaster Salvage

Robert Fuchs (2014) writes of the collapse of the Cologne Historical Archive and the efforts to save parchment and paper scraps from the building ruins.

Extreme Parchment Conservation References | top

Techniques for in situ Treatment of Parchment Book Blocks

Humidification and Flattening

It is possible to dry and flatten joined parchment sheets using a tensioning method (Burns and Bignell 1993). Multiple sheets are often legal documents which were joined using official seals or a lacing system designed to prevent tampering. Many of these systems can not be undone without doing permanent damage to these auxiliary materials or to the area of overlap with the sheets. Where the sheets are joined with cords, threads, or ribbons the condition of these materials must also be considered. It may be preferable to settle for a document that is "flat enough" and still maintains its original configuration. If a multiple-sheet document is pressed as a unit, the amount of humidification and pressure it is exposed to should be very moderate, and a thin non-stick material such as smooth spun-bonded polyester should be inserted between all sheets to prevent their sticking together.

Sometimes the top sheet of a multiple-sheet document may be more cockled than the successive sheets, and the treatment goal may be to increase the flatness of just that sheet. In that case the sheet can be humidified while remaining attached using Gore-Tex and blotters or any other system for local humidification (see Humidification and Local Treatment) and isolating it from the sheets underneath using polyester film. Similar techniques have been used for parchment book pages that remain in the binding. The document can then be weighted under felts, or the single sheet can be dried under tension (see below). It is also possible, with careful planning and dexterity, to tension all of the multiple sheets at once (see Burns and Bignell 1994).

Repair of Parchment Leaves

FitzGerald 2018;

Book of Dimma: Gillis and Meehan 2017

Cains 1996 Complete Binder

Spine Adhesive Reduction

Magee 2019; Avery 2019.

Rebinding

Providing rebinding instructions is beyond the scope of this page; there are many historical methods and modern conservation-friendly changes to consider and the topic may deserve a page of its own. For now, please consider the following:

Rebinding a parchment book block in the correct type of binding is essential to its long term preservation. Because of parchment's hygroscopic nature, the parchment can expand and deform with environmental changes, resulting in a wedge-shaped book that is much thicker at the fore edge than at the spine. Bindings for medieval manuscripts nearly always had wooden boards and fore edge clasps to keep the book blocks from expanding; even later replacement bindings often include these features. While many institutions now house their medieval manuscripts in individual boxes (providing compression) in environments with controlled temperature and relative humidity (preventing dimensional changes), some parchment manuscripts are so large and heavy that they would still benefit from the support of a wooden board binding over a modern binders board one.

Emily Lynch (2016) has proposed using conservation materials to create a medieval-style binding. The book block is resewn on double cords and laced into boards made of laminated mat board. A medieval-style endband is sewn through a slotted linen spine lining. The book is then covered in linen. The argument for using linen and mat board rather than the traditional wood and leather is based on the first two materials passing an Oddy test and latter two materials not passing. While there may be appropriate circumstances for using conservation materials instead of traditional (availability of materials and funding to procure them, for example), caution should be used before automatically rejecting materials based on artificially induced degradation studies. While it is not known if medieval wood and leather would pass an Oddy test, that is what most medieval bindings were made of and those bindings have clearly not caused catastrophic damage to the parchment within.

Parchment Book Blocks References | top

Removal of Previous Restorations

Sometimes repair efforts from years back no longer serve their purpose and must be removed. Doing so comes with considerations, as there are many situations where the removal of previous repairs on a parchment artifact is not advisable. Parchment that has been degraded by mold, or that is weak and perforated from acidic inks or paints, might be further damaged in the process of repair removal. In these cases one has to weigh the benefits that might be achieved by removing previous repairs, such as revealing obscured text or design or by improving the flexibility of the original parchment, against the possibility of causing further damage.

Another consideration is the historic nature of the repair. Once it has been determined that the repair is not original to the object it is important to decide whether or not it is important to retain as part of the history of past treatment. If the repair is actively causing damage, or obscuring a significant portion of the artifact, it probably should be removed. However, appropriate written and/or photographic documentation should be carried out prior to treatment, in order to record the location and appearance of a repair that is considered particularly interesting or historic.

The decision to remove old repairs might also be affected by the nature of the artifact and the context in which it will be used and displayed after treatment. For example, there might be more compelling reasons to remove old repairs from fine art prints and drawings on parchment, or a finely painted manuscript leaf, where the aesthetic appearance of the object is of primary concern.

For descriptions of how historic treatments on parchment were carried out, see BPG Parchment Historic Treatment Methods and Materials.

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Local Repairs

Past repair techniques were most likely executed using patches of new parchment or paper adhered with either a collagen based adhesive or paste. If the adhesive is dried out, and if the original parchment is considered strong enough in that area, it may be possible to remove the repair patch and the adhesive residue by mechanical means. Otherwise it may be necessary to locally humidify the repair, by either direct application of an alcohol/water solution (if the repair is relatively small in size) or with a piece of dampened blotter using either polyester web and/or Gore-Tex as an interleaf. Once dampened the adhesive residue can be removed with a microspatula or similar type of tool. Additional methods of adhesive removal, using poultices and saliva-dampened swabs, are described in Cleaning Methods: Adhesive Residues.

Although most sewn repairs found on parchment artifacts tend to be contemporary with the original, having been executed either by the parchment maker or by someone involved in the fabrication of the object, it is not unusual to occasionally find these types of repairs dating to a much later period in the history of the artifact. In some situations it might be difficult for the conservator to distinguish between an original or contemporary sewn repair from one that has been executed at a much later date. Careful examination of the nature of the damage, the way in which the repair has been executed and the material used for sewing (whether linen, cotton or silk thread, parchment thong or sinew), can be helpful in making these distinctions. If a sewn repair is not causing any obvious damage to the artifact, and if it is stable and not disfiguring in any way, it might be more preferable to leave it in place than to remove it.

A variety of tapes are often found on parchment artifacts, used either as hinges for single manuscript leaves, prints and drawings or as repair materials. Gummed fabric tapes and glassine tapes usually respond well to moisture. These can often be safely removed using the same methods described for parchment and paper patches above. In both cases, however, it is important to contain the moisture within the area of the repair and avoid creating tide lines with water or water/alcohol solutions. Weak and perforated skins are more susceptible to mechanical damage and removal of repairs from these areas needs to be performed with even greater care, so that the original parchment is not put under any kind of strain. Skins damaged by mold tend to have a more fibrous or pulpy texture and are very susceptible to staining and discoloration from moisture and pressure. In these cases one should use the minimal amount of moisture that is required to remove a repair with a water-soluble adhesive.

When pressure-sensitive tapes are found on parchment artifacts the best procedure is to remove the carrier along with the bulk of the adhesive mass, without driving the adhesive any further into the skin. When the tape is quite old and deteriorated the adhesive mass may have already cross-linked and become very hard and crusty. If, however, the adhesive is still relatively soft it may be possible to use a microspatula, dipped in an appropriate solvent, to slide underneath the tape and release the carrier. Although one must be extremely cautious in using heat near parchment another technique that can sometimes be considered is the use of a heated microspatula for the removal of pressure-sensitive tape. In this case the microspatula is warmed on a hot plate, or on the bottom of a tacking iron, and then used in a slicing action from one end of the tape to the other in order to release it from the object. During this procedure pieces of silicon release paper or siliconized Mylar can be placed under the carrier that has just been lifted, in order to prevent it from reattaching itself to the object. When using this technique one should be careful not to heat the microspatula beyond the temperature that is needed to release the tape carrier. Too much heat will cause the softened adhesive to be driven into the skin and may also cause damage to the parchment support. Residual adhesive can then be removed in a variety of ways, depending upon the condition of the original parchment. The adhesive can be softened in a solvent vapor chamber and then carefully scraped off the surface using a microspatula. Different types of erasers, particularly vinyl or crepe erasers, can be useful in balling up the adhesive residue which is then picked off the surface with tweezers. If the adhesive residue is still somewhat soft and sticky the use of liquid solvent, applied with a brush or with swabs, may only drive the material further into the skin making it even more difficult to remove. Sometimes, however, liquid solvent can be successfully used in combination with poulticing materials such as Fuller's Earth, or with a suction disc. All of these techniques are similar to those that have been developed for paper artifacts and are described in greater detail in Hinge, Tape, and Adhesive Removal.

Backings and Mounts

As C. Clarkson states (1980), one of the many unsympathetic ways parchment leaves have been treated has been to “ignore its life and spirit altogether by humidifying it and then sticking it down overall to a card, paper, or wood” or by “drumming it down” (i.e., adhering only the edges of the artifact to a heavy card). These methods unnaturally restrain the skin in such a way that it fights against the mount, often resulting in ruptures or splits in the weaker areas of the skin.

Mounts Adhered with Paste or Glue: When separating a parchment support from a paper or cardboard mount, most of the paper and adhesive residue should be removed mechanically and as dry as possible before introducing any moisture. A parchment leaf should never be immersed in a water bath to remove it from a mount, as might be done occasionally with a paper artifact.

When removing a parchment support from a mount or backing, care should be taken to keep the parchment support flat and in plane, not bending or flexing the support in any way, especially if it has a thick design layer on either recto or verso surfaces. Any actively flaking pigments or inks should be consolidated prior to treatment (See Consolidation of Media.) The leaf is placed face down onto the smooth side of a sheet of Gore-tex or smooth hollytex. Using the edge of a sharpened Casselli knife, metal spatula, or very thin lifting folder, the backing card is slowly delaminated layer by layer down to the final layer of paper that is adhered directly to the verso of the parchment support.

Only at the final stages of the backing removal should small amounts of moisture be introduced to remove the last paper fibers (using a swab and an ethanol and water mixture) and adhesive residue (using saliva and a swab). These residues are removed in small sections, being constantly mindful not to affect any text ink or design that might be extant on the verso of the support. As complete a removal of any adhesive residue as possible is especially important when dealing with parchment, otherwise these residue layers can create an uneven contracting effect over the surface of the leaf. But if text ink or design does exist on the verso surface, a thin layer of adhesive may have to be left over areas of design should its removal affect the design in any way.

Mounts Adhered with Heat or Solvents: Dry mounted parchment that is reasonably strong and healthy, and not weakened by mold, has been successfully treated using mechanical tech-niques. In general, the nature of parchment's surface characteristics do not allow for a strong bond with dry mount adhesive and so in most cases the skin separates rather successfully. Working with the object face up and beginning in one corner, a Teflon spatula can be inserted between the parchment and the mount, causing the skin to lift away from the dry mount adhesive By viewing in raking light the little residual adhesive that remains on the verso can be removed by swabbing with cotton balls dipped in hexane. (JFM)

Laminations

Silk crepeline was frequently used for the lamination of paper and parchment artifacts, before the introduction of heat-activated laminating films. Depending on the relative strength of the skin and the condition of the media, crepeline has been mechanically removed from parchment without too much difficulty, especially when the silk fabric is already partially degraded and if the paste has dried out. In this case, the problem is the removal of the remaining paste which the conservator may opt to leave. Because silking is a wet process that utilizes pressure, there are documents in which the fabric and adhesive are enmeshed to both the surface of the media and the support. It is likely that the silk will not release without loss or alteration of the media. If moisture is needed to release the adhesive bond that holds the fabric in place, further damage could be caused to the support as well as to any water-soluble media that might be present.

Goldbeater's skin was sometimes used in the past for the lamination of weak and degraded parchment manuscripts and documents. Since gelatin or parchment size was more commonly used to attach the transparent membrane it usually remains well-adhered to the original artifact. The moisture that would be necessary to swell the adhesive and release the membrane could cause considerable damage to the parchment support and the media. Therefore it is often best not to attempt the removal of a lamination with goldbeater's skin.

A German-made laminating film, Mipofolie, was occasionally used in Europe during the 1950's for the lamination of parchment manuscripts weakened by mold or corrosive inks and paints. Two cases reported success in delaminating important illuminated codices in a bath of 1/4 amyl acetate/ethanol. They did not feel that the solvent bath had any negative effect, except for a possible migration of a small amount of adhesive into the parchment structure in the case of one sheet. Their greatest concern after removing the film was to make sure that no sticky adhesive residues remained on the surface, and some clean-up of such residues was necessary after each bath. The efficacy of the bath was speeded up by both mechanical lifting of the edges of the films, and by piercing the film with a needle in problem areas. In both cases the leaves were immersed briefly, just long enough to permit mechanical detachment of the film with slight effort. (Wouters et al. 1990, and Wächter 1987.)

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Heat is generally not suitable for removing thermoplastic backing adhesives, because of the hazards heat poses to parchment. Purely mechanical methods of removal may be preferable for smooth, hard parchment surfaces. For removal of dry mounted parchment. In many cases, however, organic solvents are needed. As with pressure-sensitive tapes, solvents may be applied sparingly with a brush to soften or swell the adhesive and then the lamination or backing can be removed mechanically with as much force as the condition of the parchment will permit. Backings can also be exposed to solvent fumes in a vapor chamber to facilitate mechanical backing removal. It may be necessary to return the parchment to the solvent chamber several times in the course of backing removal in order to resoften the adhesive.

When very degraded parchment has this type of backing, the parchment may be unable to withstand any mechanical activity, and a solvent bath may be considered. The hazards of this drastic treatment must then be weighed against the benefits of the backing removal, and the decision may be made to leave the backing undisturbed. Even if the backing can be successfully removed, if the adhesive can not it can cause problems because of an exposed sticky adhesive layer, or because a hardened adhesive layer might cause cockling when it is not restrained by the backing. As always the benefit of the treatment must be weighed against its costs.

Lubricants

Sometimes parchment is lubricated overall with organic materials such as petroleum jelly, lanolin, oils, or other widely varied substances in a misguided attempt to “nourish” or “condition” the parchment, similarly to the way leather used to be routinely treated. Many of these lubricants are damaging to parchment, as they can darken the skin and/or leave a sticky residue on the surface which traps dirt and contaminates materials with which it comes into contact. It is certainly desirable to remove these lubricants whenever possible, and to the extent possible. This generally means either wiping the entire surface with cotton dampened with organic solvent or, rarely, immersing the artifact in a solvent bath. Certainly the former approach subjects the item to less risk from exposure to solvent, while entailing greater risk from abrasion of the surface. Another possible approach is to press a series of papers or blotters wet with the appropriate solvent on the surface of the artifact to wick away the lubricant. The paper should not be allowed to dry in contact with the parchment surface, to avoid the danger of its becoming adhered. It is not possible to remove every trace of lubricant from parchment, and the hazards involved in the chosen treatment should be weighed against its benefit. It may be wiser in some cases to settle for removing only enough lubricant to eliminate the stickiness from the surface.

Previous Binding Campaigns

Removal of Previous Restorations References | [top]

Media Consolidation

[Copied from original BPG Parchment page]

(See Consolidation, Fixing, and Facing, and Adhesives.)

The adhesion strength of the design layer to a parchment support is a function of a number of factors: a) the preparation of the parchment surface; b) the painting, drawing, or printing media; and c) the state of preservation and subsequent damage suffered by either the media and/or the parchment support. Only after assessing the condition of the design layer, and establishing that active flaking is occurring and determining its cause, can an appropriate consolidant and method of application be determined.

As S. Keck (1969) states, the deterioration of a paint layer can be the result of any number of chemical, physical, or biological agents, resulting in mechanical damage. In works of art and documents on a parchment support, this mechanical damage usually takes the form of cracking, lifting, or increased friability of the design layer. The most common problem affecting a painted design on parchment is the cracking and flaking that results from the over-handling (flexing and folding) or unrestrained movement of the parchment support (in response to humidity and temperature fluctuations), or from direct abrasion and manipulation of the design layer. Additionally, severe flake loss can occur to a design layer if the parchment support has been inadequately prepared (if the hair-side of the skin is left too slick, for instance) or if the skin has been treated with a surface coating, as in the case of Byzantine manuscripts. (See Unique Qualities of Parchment as a Support: Surface Qualities.)

Furthermore, the binders of some pigments may be affected by environmental factors, condition factors (water damage, biological attack), neighboring pigments, or possibly even by the chemical constitution of the parchment support itself, causing them to become increasingly friable and powdery. Moreover, certain pigments may themselves be agents of flake loss; for instance, lead white, which is often thickly applied and is a brittle paint film, is highly susceptible to flaking; copper green (“verdigris”) can become friable as it reacts with the parchment support; iron-gall ink may also react with uppermost layer of parchment support; medium-rich organic glazes can develop a fine craquelure and sometimes cause the opaque pigment on which they are painted to crack and flake while unglazed areas of the design remain intact.

In short, it is essential to consider all these factors (the type of mechanical damage suffered by the paint layer, the pigments, the media, and the preparation of the parchment surface) before proceeding with a consolidation treatment. Consolidation is never fully reversible, even with good quality materials. As such, considerable care is of essence.

It should be mentioned that gentle humidification and flattening of the parchment support (see Humidification and Flattening/Tensioning/Drying) has been used as an indirect method of consolidating the design layer, thereby rehydrating the pigment layer and aiding the medium to “reconstitute” its adhesive power (Yow,; Cains 1982/83). But if the medium is largely degraded, leaving the pigment powdery and friable, humidification may have little effect.

Choice of Consolidant

The most prevalent binders used for manuscript paintings and inks on parchment include glair, gum arabic, and isinglass (sturgeon glue), all of which can remain water soluble after drying. With this in mind, the many consolidants that have been suggested and tried by conservators around the world over the last thirty years can be divided into aqueous and non-aqueous consolidants.

Aqueous Consolidants

The argument for using a consolidant such as parchment size or gelatin is that they are proteinaceous substances and are similar to the media of manuscript inks and pigment and are more sympathetic to a parchment support than synthetic materials. A water soluble consolidant should be used with extreme care so as not to dissolve water-sensitive pigments, especially organic glazes, and so as not to affect the parchment support.

Gelatin (powdered photographic grade or leaf gelatin) or parchment size (can be mixed with isopropanol to aid penetration) have been the aqueous consolidants most generally used to treat flaking pigments and inks on parchment. Other possible alternatives include isinglass (as suggested by Petukhova and Bonadies 1993), natural gums, and funori; but these have not been widely tested or used to date on parchment supports. (See Adhesives and Consolidants.)

Non-aqueous Consolidants

(See Adhesives and Consolidants.):

Among the many solvent-based consolidants that have been suggested for flaking or friable media on parchment are methyl methacrylate (Cains 1982–83); methyl cellulose in ethanol for powdery matte pigments (Quandt 1992); cellulose acetate; methyl cellulose in methylene/methanol chloride for text inks (Plossi and Crisostomi 1981); Ftorolon, a soluble fluoroplast, for friable pigments (Bykova 1976 and Yusupova 1980); VA 2 EHA, a synthetic resin (an aqueous dispersion of vinyl acetate with 2-ethylhexyl acrylate) for readhering loose paint flakes (Bykova 1976); Plexigum P-24, a synthetic resin (Giuffrida 1983); microcrystalline wax or a mixture of beeswax and dammar resin (Marconi 1960); soluble nylon (Werner 1974). Many of the following consolidants are not recommended for use.

The arguments for using a solvent-based consolidant are potential reversibility and its lack of dissolving effect on water soluble media; but a solvent-based consolidant can be difficult to control, possibly moving pigment particles in the brush application as the solvent rapidly disperses.

Local Brush Application

Local application of a consolidant is performed along cracks, within areas of flake loss, beneath lifting paint flakes, and through areas of friable pigment. With a very fine brush (00 or 000) under binocular microscope magnification, the area of loss (along the exposed edges of the paint film) is lightly painted with the consolidant. Capillary action from the liquid consolidant (either from warmed gelatin or parchment size, or from the solvent base in a non-aqueous consolidant) carries the consolidant beneath the paint flake and anchors it to the support.

The setting of the consolidant and firm anchoring of loose paint flakes can be aided by the use of a secondary tool, such as a bamboo or teflon point, or spoon shaped dental tool followed by gently pressing with an interleaving of silicon coated mylar or silicon release paper. For paint layers signifi-cantly softened by the consolidant application, it may be necessary to allow a brief setting period, before pressure is applied to avoid transfer of the softened paint to the release paper. (See Hazards).

Parchment size and gelatin should be applied warm to facilitate penetration and capillary action; but neither should be overheated or they will become denatured and lose their adhesive strength. Extreme care must be taken while working with a local consolidant to maintain a consistent and relatively thin viscosity. The consolidant should not be allowed to become too thick while working (from the evaporation of the solvent or from prolonged heating causing the evaporation of water). If the consolidant is too viscous, the brush will pick up more flakes than it will successfully anchor to the support, creating potentially disastrous consequences. In addition, an excessively viscous consolidant will not flow under the flakes of paint or ink but instead will be deposited on the surface of the media, leaving a shiny residue.

Spray Application

The spray application of a consolidant is particularly effective for the treatment of broad areas of flaking or friable design, for instance when a text ink is flaking throughout a manuscript. Fine droplets of the consolidant are delivered by an artist's pneumatic air brush over a broad area of the design and the parchment support. It should be noted, however, that a spray application may not be appropriate for a heavily gilded area, for the consolidant will not penetrate but will remain on the surface of the metal leaf.

Without Vacuum Suction Table: The spray application of a consolidant was first introduced in the manuscripts conservation literature to treat not only flaking inks and pigments, but also to soften horny areas and consolidate weak areas of the parchment support (Wächter 1962), using a solution of parchment size, alcohol, and vinegar. (See Consolidation of Degraded Parchment.) This technique is used in combination with pressing between blotters, and weights for drying and flattening of the leaves. Particular care must be taken to not over-wet the parchment while spraying, and to use very light weight during pressing so as not to cause offsetting of the pigment layer. More recently this practice has been used in Europe (Wächter 1987) and elsewhere (CCAHA, Philadelphia) without the addition of vinegar in the consolidant solution. The use of B-72 in di-ethylbenzene has been recommended as a spray consolidant for powdery matte paint on wooden ethnographic objects (Welsh 1980), but has not been applied to inks and pigments on parchment to date.

With Vacuum Suction Table: By combining the spray application of a consol-idant with the use of a vacuum suction table, three results are achieved simultaneously: a) the parchment support is held under light pressure, and is thereby kept flat and in plane during treatment; b) the parchment support dries quickly and is not allowed to stay damp long enough to cause dimensional change; c) loose paint flakes are anchored immediately to the support by suction during treatment. The treatment of single parchment leaves employs a traditional vacuum suction table (Quandt 1986; also Maggen 1991), while the consolidation of flaking inks and pigments within a bound manuscript employs a wedged-shaped vacuum suction platen, first described and designed by S. Michalski for in-situ book repair (Quandt 1991). Care must be taken especially for works with design on both sides of the parchment support: the amount of suction should be carefully controlled and monitored so as not to pull loose inks off the verso or underside of the support during treatment. This can be avoided by briefly pre-treating the verso or underside of the support with spray consolidant before moving to the suction vacuum table. (Quandt 1991.)

Applied as an Ultrasonic Mist

Designed and developed by Stefan Michalski (1990) of the Canadian Conservation Institute, the ultrasonic mister delivers the consolidant as a very fine mist (1/10th the size of droplets from a pneumatic airbrush or spray gun), providing greater control and more effective penetration of the pigment layer. The mister was developed for consolidating powdery, binderless paints (as on ethnographic objects), has been applied to the consolidation of pastel and other media on paper artifacts (Weidner 1993). The technique has not yet been applied to media on parchment, but offers great potential for reducing some of the difficulties of a spray treatment. (See Consolidation of Media.)

Hazards

Mechanical Problems Affecting Design

Flake loss to an already fragile design can be aggravated during the course of a consolidation treatment, either by local application with a brush or by using a spray on the vacuum table. Moreover, if the consolidated area is pressed too soon after treatment while the consolidant or pigment medium is still wet, or if too much pressure is applied, offsetting and irreversible deformation to the surface texture of the design can occur.

Changes in Appearance of Pigments

The visual appearance of the design layer can be irreversibly damaged by an over-application of consolidant by using brush or spray. For instance, an aqueous consolidant could re-solubilize the pigments during treatment; a consolidant could saturate matte colors and change its reflectance; an overly liberal application of consolidant could change surface gloss of pigments; and too much solvent or too aggressive a solvent could carry pigment particles away from their boundaries, causing a halo effect, or drive the pigment into the fibers of the skin. In addition, the suggestion has been made (Fuchs 1991) that many organic colorants and inks used in manuscript paintings are pH sensitive and may be adversely affected by the pH of such consolidants as gelatin and parchment size, but research into this question has not yet been made available to conservators. Ultramarine is known to be pH sensitive and can be dissolved by acetic acid. (Gettens and Stout p.166.)

Depending on the recipe used gelatin or parchment size can vary widely in their pH. An adhesive made from unrinsed parchment clippings will contain more alkaline calcium compounds, and a higher pH, than one made from rinsed parchment. Gelatin usually has a mildly acidic pH of about 5.5. If acetic acid is added to gelatin it's pH will fall below 5.0. Acetic acid will also lower the pH of parchment size, but not to the same extent as with gelatin.

Changes to the Parchment Support: An overly liberal application of a consolidant could leave visible residues on the surface of the parchment support as well as change the surface characteristics of the skin. Moreover, if the consolidant is allowed to over-penetrate the support and is then weighted with too much pressure, the parchment could become darkened or even translucent in some areas. One question that has yet to be studied is whether the application of a consolidant to selected areas of a sheet of parchment will cause differential tension between treated and untreated areas of the skin.

Problems with Unstable, Damaging, or Irreversible Consolidants: The past uses of such unstable and irreversible consolidants as soluble nylon or cellulose nitrate (See O. Wächter discussion of “Zapon varnish,” 1982) provide cautionary evidence of the potential hazards of media consolidation. Moreover, the question of reversibility is a particularly vexing one with regard to the consolidation of media on a parchment support such aqueous consolidants as parchment size and gelatin are obviously irreversible when used on the water-soluble media found in manuscript text inks and illumination; but the reversibility of solvent-based consolidants is also a question if certain solvent treatments are potentially damaging to the collagen structure of the support. (See Potential Alteration/Damage to Object in Treatment: Problems Caused by the Use of Organic Solvents and Solvent Treatments.)

Media Loss Compensation

In general, loss compensation (i.e. inpainting) of media on parchment supports is not performed. A lack of a varnish-like protective barrier over the paint surface (unlike on oil or tempera paintings on canvas or wooden supports) that can isolate the original pigment from modern additions makes inpainting difficult or impossible to remove, and, therefore, an ethically unsound treatment option. Given the advances in technology, digital reconstructions of damaged manuscript paintings are relatively straightforward to produce and are recommended over attempts to manually restore losses.

There are many extant examples of illuminations that have been inpainted or overpainted by 19th- and 20th-century restorers, who often used pigments of similar color but different mineral composition to the original. These pigments can sometimes be detected by photographic techniques involving ultraviolet and infrared (false color) illumination.

Media Consolidation References | [top]

References

Factors to Consider

Materials for Parchment Treatment

Surface Cleaning

Humidification

Kenney, Kathryn. 2022. "Preserving Evidence of Use: The Conservation of a Teaching Collection of Medieval Manuscript Fragments." Guardians of Memory: Preserving the National Collection (blog). The Library of Congress. March 3, 2022.

Flattening

Repair and Filling Losses

Baldwin, Jessica, and John Gillis. 2006. "Conservation of a Thirteenth-Century Biblia Sacra Latine." Edited by Gillian Fellows-Jensen and Peter Springborg. Care and Conservation of Manuscripts 9: 58–68.

Cains, Anthony. 1992. "A Facing Method for Leather, Paper and Membrane." In Sheila Fairbrass, editor, Conference Papers Manchester 1992, The Institute of Paper Conservation, 153-157.

FitzGerald, Solange. 2018. "A Less Invasive Treatment Solution for a Bound Seventeenth Century Parchment Volume." Journal of the Institute of Conservation 41 (2): 169–78.

Jordan, Tammy. 2011. "Using Magnets as a Conservation Tool: A New Look at Tension Drying Damaged Vellum Documents." Book and Paper Group Annual 30: 47–55.

Quandt, Abigail B. 2021. "Recollections of Tony Cains and His Approach to the Treatment of Parchment Manuscripts." JOURNAL OF PAPER CONSERVATION 22 (1–4): 156–79.

Watanabe, Mariko. 2017. "Reconstituted Parchment: Its Physical Properties and Suitability as a Repair Material for Parchment Bindings." Restaurator 38 (2): 127–51.

Parchment Book Blocks

Cains, Anthony G. 1996. "Roger Powell’s Innovation in Book Conservation: The Early Irish Manuscripts Repaired and Bound, 1953-1981." Edited by John L. Sharpe. Roger Powell: The Compleat Binder, Bibliologia, 14:68–87.

FitzGerald, Solange. 2018. "A Less Invasive Treatment Solution for a Bound Seventeenth Century Parchment Volume." Journal of the Institute of Conservation 41 (2): 169–78.

Gillis, John, and Bernard Meehan. 2017. "Examining the Book of Dimma, the Scribe Dianchride and Gospel of John." In An Insular Odyssey: Manuscript Culture in Early Christian Ireland and Beyond, 86–113. Dublin: Four Courts Press.

Lynch, Emily. 2016. "An Alternative Approach to Rebinding Medieval Manuscripts." The Morgan Library & Museum.

Extreme Parchment Conservation

Fuchs, Robert. 2014. "The Collapse of the Cologne Historical Archive: The Role of Restorers and Emergency Plan." Edited by M. J. Driscoll. Proceedings of the Fourteenth International Seminar Held at the University of Copenhagen 17th-19th October 2012, Care and Conservation of Manuscripts, 14:17–42.

Gillis, John. 2021. The Faddan More Psalter: The Discovery and Conservation of a Medieval Treasure. Dublin, Ireland: National Museum of Ireland.

See also: Fallen, Oliver. 2019. Treasure From The Bog. (Documentary on YouTube)

Pal, Kazim, Nicola Avery, Pete Boston, Alberto Campagnolo, Caroline De Stefani, Helen Matheson-Pollock, Daniele Panozzo, et al. 2017. "Digitally Reconstructing the Great Parchment Book: 3D Recovery of Fire-Damaged Historical Documents." Digital Scholarship in the Humanities 32 (4): 887–917.

Removal of Previous Restorations

Media Consolidation

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Bibliography

[Copied from original BPG Parchment page.]

Allington, Caroline. 1982. "Animal Products." In The Care and Conservation of Fans. London: Institute of Archaeology, University of London.

"A Note on the Conservation of Some Parchment Documents Damaged by Fire." 1970. Business Archives: The Journal of the Business Archives Council 33: 18-19.

Ballago, Mrs. Laszlo and Maria Czigler. 1992. "The Restoration/Conservation of an Outsize Eleventh Century Parchment Gradual." In Papers of the Conference on Book and Paper Conservation held in Budapest 4-7 September 1990 edited by Beatrix Kastaly. Budapest: Technical Association of Paper and Printing Industry and the National Szechenyi Library, 306-308.

Banik, Gerhard. 1990. "Conservation of Water Damaged Museum and Archival Documents." ICOM Preprints II 9th Triennial Meeting, Dresden 26-31 August, 1990. 443-446.

Banou, Penelope and Stassinou, Angeliki. 2012. "Approaches to the Conservation of Patriarchal Sigillia on Parchment from the General State Archives of Greece." Journal of the Institute of Conservation 35(2): 201-218.

A very detailed article describing the ethical issues, conservation treatment and rehousing of four post-Byzantine Patriarchal sigillia (deeds). Sigillia are large documents written on parchment, most of these include a tongue-like projection and a pendant lead seal adhered to bundles of twisted or braided colourful silk threads. The tongue-like projections have a set of lacing holes in them, the silk threads were then passed through them, forming a pattern. The sigillia were then folded into packages for sending. These folds resulted in hard creases or distortions in the parchment’s surface. The conservators discussed the difficulties of opening the substrate flat without disturbing the original features. They had to take into consideration the inks used to write the document, as well as the silk threads and lead seals, before devising a method of treating the sigillia. The documents also had to be stored and hinged in a unique way, to provide the correct support for all the components attached. The documents were placed in either double or triple window mounts made of archival paper boards. The parchment was kept in place using Melinex corners and straps, without applying tension to the parchment. Ethafoam was used to isolate the lead seals, and a Melinex film barrier was placed to avoid contact between the lead and buffered mount boards.

Bansa, Helmut. 1980. "Restaurierung von Buchmalerei." Maltechnik Restauro 2: 93-95.

Bansa, Helmut. 1982. "Polyglykol fur Pergament." Maltechnik: 274-277.

Baynes-Cope, A. D. 1988. "Ethics and the Conservation of Archival Documents." Journal of the Society of Archivists 9: 185-187.

Beaufort, Thomas Richard. 1926. Pictures and How to Clean Them, to which are added notes on things useful in restoration work. New York: Frederick A. Stokes.

Belaya, I.K. 1969. "Instructions for the Softening of Parchment Manuscripts and Bookbindings." Restaurateur 1:20-48, 49-51.

Belaya, I.K. 1969. "Selecting and Testing Adhesives for the Restoration of Skin-bindings and Parchments." Restaurator 1: 221-231.

Beöthy-Kozocsa, Ildikó; Sipos-Richter, Teréz and Györgyi Szlabey. 1987. "Report on Parchment Codex Restoration Using Parchment and Cellulose Fibre Pulp." ICOM Preprints II 9th Triennial Meeting, Sydney, 1987: 641-648.

Bervas, Marianne. 1991. "La Restauration de Miniatures sur Parchemin." Sauvegarde et Conservation des Photographies, Dessins, Imprimes et Manuscripts, Actes des Joumees Internationales d'Etudes de l'ARSAG, Paris, 30 Septembre au 4 Octobre 1991, 152-156.

Bruce, James. 1982. "A Survey of the Original Binding and Rebinding Techniques of Registers in the Queensland State Archives." The Paper Conservator 7: 8-14.

Bull, William. 1987. "A 17th Century Ethiopic Bookbinding." The Abbey Newsletter 11(3): 44-5 .

Burns, Thea and Margaret Bignell. 1993. "The Conservation of the Royal Charter and Great Seal of Queen's University." The Paper Conservator 17: 5-12.

Bykova, G.Z.; Ivanova, A.V. and I.P. Mokretzova. 1978. "Conservation Methods for Miniature Paintings on Parchment: Treatment of the Paint Layer." In Conservation and Restoration of Pictorial Art, edited by Norman Brommelle and Perry Smith. London: Butterworths: 207-9.

Bykova, G.Z. 1993. "Medieval Painting on Parchment: Technique, Preservation and Restoration." Restaurator 14(3): 188-197.

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Cains, Anthony. 1992. "Parchment Repair." Proceedings of tile Society of Archivists Annual Instructional Meeting, Belfast.

Cains, Anthony. 1982. "Repair Treatments for Vellum Manuscripts." The Paper Conservator 7: 15-23.

Cains, Anthony. 1987. "Repair Treatments for Vellum Manuscripts." In Library Conservation and Archive Materials and the Graphic Arts, edited by Guy Petherbridge. London-Boston: Butterworths, 183-194.

Calabro, Giuseppe et al. 1986. "An Evaluation of Softening Agents for Parchment." Restaurator 7: 169-180.

Chahine, Claire. 1991. "Travaux realises en France dan la domaine de parchemin." In Pergament, edited by Peter Rück. 195-202.

Clarkson. Christopher. 1995. "Preservation and Conservation of Library and Archive Collections." Paper Conservation News 74: 6-7.

Clarkson, Christopher. 1992. "A Conditioning Chamber for Parchment and Other Materials." The Paper Conservator 16: 27-30.

Clarkson, Christopher. 1975. "Limp Vellum Binding and its Potential as a Conservation Type Structure for the Rebinding of Early Printed Books. A break with 19th and 20th Century Rebinding Attitudes and Practices." Preprints of the 4th ICOM Triennial Meeting, Venice, 13-18 October 1975. 1-15.

Cockerell, Douglas. 1939. "Condition, Repair and Binding of the Manuscript." In Scribes and Correctors of the Codex Siniaticus, edited by H.J.M. Milne and T.C.Skeat. London: The British Museum, 70-86.

Cockerell, Sydney Morris. 1958. The Repairing of Books. London (2nd edition, 1960).

Das, Sudhir Kumar and Ranbir Kishore. 1983. "Repair and Restoration of Parchment and Vellum Manuscript." Conservation of Cultural Property in India 16-17: 181-3.

Dernovskova, J. and I. Hofmanova. 1994. Conservation of Parchment Documents, 9th Seminar restauratoru a historiku, Trojanovice.

Dernovskova, J., H. Jirasova and J. Zelinger. 1995. "An Investigation of the Hygroscopicity of Parchment Subjected to Different Treatments." Restaurateur 16:I.

Dignard, Carole. 1992. "Tear Repair of Skins with Minimal Access to their Backs: The Treatment of a Kayak." Leather Conservation News 7(2): 1-8.

Dirda, Marian. 1984. "Synthetic Linings." Washington Conservation Guild Newsletter 8(1).

Dobrusina, S. A. and V. K. Visotskite. 1994. "Chemical Treatment Effects on Parchment Properties in the Course of Aging." Restaurateur 15: 208-219.

Dobrynina, E. and G. Bykova. 1998. "Study and Conservation of the Fourteenth-Century Illuminated Greek Manuscript 'Akanthistus to the Virgin." Proceedings of IPC 21st Anniversary Conference London, 6th-9th April 1997: 200-5.

Drayman, Terry. 1968. "The Conservation of a Petrarch Manuscript." Journal of the Walters Art Gallery 31-32: 119-123.

Dreibholz, Ursula. 1983. "A Treasure of Early Islamic Manuscripts on Parchment: Significance of the Find and Its Conservation Treatment." AIC Preprints, Baltimore, Maryland, 11th Annual Meeting (May 25-29, 1983): 30-38.

Dreibholz, Ursula. 1983. "A Treasure of Early Islamic Manuscripts on Parchment: Significance of the Find and Its Conservation Treatment." AIC Preprints, Baltimore, Maryland, l lth Annual Meeting (25-29 May 1983). 30-8.

Dreibholz, Ursula. 1987. "The Marburg Parchment Colloquium." The Abbey Newsletter 11(8): 132-135.

Dreibholz, Ursula. 1991. "Der Fund von Sanaa: Fruhislamische Handschriften auf Pergament." In Pergament, edited by Peter Rück. 299-314.

Dreibholz, Ursula. 1994. "Conservation of Early Koran Fragments." Paper Conservation News 69: 10.

Duret-Robert, Francois. 1983. "Les evantails francais." Connaissance des Arts 371: 83-8.

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Ellement, Peter G. 1987. "A Note on the Structure of Vellum and the Effects of Various Solvents." In Guy Petherbridge, editor. The Conservation of Library and Archive Materials and the Graphic Arts. London: Butterworths, 199-200.

Ellis, Margaret Holben. 1980. "Drawings on Parchment: Special Conservation Problems for Collectors." Drawing 2(4): 85-86.

Ellis, Margaret Holben. 1987. The Care of Prints and Drawings. Nashville, Tennessee: The American Association of State and Local History. (more recent editions available)

Ellis, Roger. "The Principles of Archive Repair." In Library Conservation: Preservation in Perspective, edited by John P. Baker and Marguerite C. Soroka. Stroudsburg, PA: Dowden, Hutchinson & Ross, 316-324.

Farkas, Csilla. 1992. "The Problems of Conserving/Restoring a Corvinus Manuscript Covered in Velvet." In Papers of the Conference on Book and Paper Conservation held in Budapest 4-7 September 1990, edited by Beatrix Kastaly. Budapest: Technical Association of Paper and Printing Industry and the National Szechenyi Library, 164-173.

Fitzsimons, Eileen. 1986. "Limp Vellum Bindings: Their Value as a Conservation Binding." Restaurateur 7(3): 125-42.

Flamm, Vera and Karin Troche. 1998. "A New Approach to Flattening a Pastel Picture on Parchment by J. E. Lyotard depicting Empress Maria Theresa." Proceedings of IPC 21st Anniversary Conference London, 6th-9th April 1997, 206-10.

Fogle, Sonja and Toby Raphael. 1984. "Leather Conservation Terminology." Leather Conservation News 4: 6-15.

Fogle, Sonja, Toby Raphael and Katherine Singley, editors. 1984. Recent Advances in Leather Conservation. Proceedings of a Refresher Course sponsored by FAIC, June 1984, Harpers Ferry, West Virgina. Washington, D.C.: The American Institute for Conservation.

Forbes, Suzanne. 1969. The Nature and Care of Parchment and Vellum Documents. University of London, Institute of Archaeology.

Forde, Helen. 1986. Doomsday Preserved. London, England: Public Record Office.

Franck, Peter. 1964. "Vellum Binding." Guild of Book Workers Journal ll1: 11-22.

Frost, Gary. 1977. "Conservation Standard Rebinding of Single Books: A Review of Current Practices at the Newberry Library." Preprints of the 5th AlC Conference Boston, 30th May to 2nd June, 56-61.

Fuchs, Robert. 1991. "Der widerspenstigen Zachmung. Pergament in Struktur und Geschichte." In Pergament, edited by Peter Rück. 263-78.

Fuchs, Robert. 1991. "Blaufarbmittel in illuminierten Handschriften und Drucken - ihre zerstorende Wirkungen und restauratorische Konsequenzen." In Preprints for the 7th International Congress of Restorers of Graphic Art, 26-30 August 1991, Uppsala, Sweden, edited by K. Jonas Palm and Mogens S. Koch. 1-9.

Fuchs, Robert, Renate van Issem, Doris Oltrogge and Gertrud Schenck. 1988. "Glas oder Kunstoff? Zur Konservierung der ‘Quedlinburger Itala-Fragmente’ in der Deutschen Staatsbibliothek, Berlin (DDR)." Restauro 4: 285-291.

Fuchs, Robert. "Nolite Manuscripta Cruciare sed Conservate Potts. Uberlegungen sur Konservierung Mittelalterlicher Buchmalerei." Maltechnik: 39-49.

Fuchs, Robert. 1992. "Neue Untersuchungen zur Konservierung von mittelalterlicher Buchmalerei." In Papers of the Conference on Book and Paper Conservation held in Budapest 4-7 September 1990, edited by Beatrix Kastaly. Budapest: Technical Association of Paper and Printing Industry and the National Szechenyi Library, 295-301.

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Gairola, T.R. 1958. "Preservation of Parchment." Journal of Indian Museums 14-16: 43-45.

Gimbrère, Lucie M. and Pieter F.J. Obbema. 1985. "Restaurator und Wissenschaftler." Maltechnik Restauro 4: 52-62.

Giovannini, Andrea. 1991. "Le document d'archives en parchemin: La restauration comme moment de recherche archéologique." In Pergament, edited by Peter Rück. 239-46.

Giovannini, Andrea. 1990. "Archeologie et Restauration des Livres et des Documents d'Archives Medievaux." Gazette du Livre Medieval 17: 7-19.

Giuffrida, Barbara. 1983. “Book Conservation Workshop Manual. Part Four: The Repair of Parchment and Vellum in Manuscript Form,” The New Bookbinder 3: 21-41.

Giuffrida, Barbara. 1974. "Limp and Semi-Limp Vellum Bindings." Designer Bookbinders Review 4: 2-7.

Giuffrida, Barbara. 1975. "Limp and Semi -Limp Vellum Bindings, Part II." Designer Bookbinders Review 5: 2-13.

Goddard, Patricia. 1989. "Humidity Chambers and their Application to the Treatment of Deformations in Fabric-Supported Paintings." The Conservator 13: 21-24.

Gowers, H.J. 1975. "The Conservation of Javanese Shadow Puppets." ICOM Preprints of the 4th Triennial Meeting, Venice 75/3/1: 1-7.

Gowers, H. J. 1959. "Treatment of a Manuscript." The Museums Journal 58(12): 278-81.

Hamburg, Doris. 1991. "The Washington Haggadah, A Conservator's Perspective." In The Washington Haggadah: Commentary, edited by Myron M. Weinstein. Washington, D.C.: Library of Congress, 171-195.

Hermanns, Johan, Pieter Hallebeek, Marion Kite and Christopher Calnan. 1992. "Fans on Skin: Their Conservation and Storage." Conservation of Leathercraft and Related Objects: Interim Symposium at the Victoria & Albert Museum, 24th-25th June. ICOM Committee for Conservation, 42-44.

Hofmanova, I. 1994. The Properties of Historical and Modern Parchment. Institute of Chemical Technology: Prague.

Horton, Carolyn. 1967. "Saving the Libraries of Florence." Wilson Library Bulletin 41: 10: 1,034-1,043.

Hughes, Christine and Tim Edwards. 1992. "Parchment Repair: A Reconsidered Approach." Proceedings of the Society of Archivists Annual Instructional Meeting, Belfast, 1992.

Ibsen, Soren. 1998. "Conservation and Restoration of Water-damaged Books." Paper Conservation News 87: 12-13.

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Jirasova, H. 1993. The Fixation of Colour Layer on Parchment. Institute of Chemical Technology: Prague.

Johnson, Rebecca. 1990. "Conservation of a Patent Document on Parchment and an Exploration of Tensioning Techniques for Flattening Parchment." Papers Presented at the Sixteenth Annual Art Conservation Training Programs Conference, April 26-28, 1990. Winterthur, DE: University of Delaware/Winterthur Museum, 21-31.

Jonsson, Axel. 1978. "Konservering och Restaurering av Pergament." Konservering og Restaurering af Læder, Skind og Pergament. Kompendium fra Nordisk Videreuddannelseskursus, 3-14 April 1978, Kulturer, Lund, Sverige. Copenhagen: Konservatorskolen Det Kongelige Danske Kunstakademi, 358-363.

Jussoupova, M.V. 1975. "Étude des Causes de l'Apparition de la Transparence des Parchemins au Cours d'un Certain Nombre de Travaux en Restauration." ICOM Preprints 4th Triennial Meeting, Venice: ICOM-CC (#75/15/16): 1-5.

Kahle, T. B. and N. Caldararo. 1986. "State of Preservation of the Dead Sea Scrolls." Nature 321 6066: 121-2.

Kahle, T. B., Anne C. Kahle and Carolyn Horton. 1980. "PVA, Oiling and Heat-set Tissue: A Debate." The Abbey Newsletter 4(1): 7-9.

Kaminitz, Mairian and Judith Levison. "The Conservation of Ethnographic Skin Objects at the American Museum of Natural History." Leather Conservation News 5(1): 1-7.

Kellar, Scott. 1988. "Case History: The Conserving of a Chained Binding." The Book and Paper Group Annual 7: 23-7.

Ketzer, Roswitha. 1994. "A Conservation Project in Kairouan." Paper Conservation News 69: 8-9.

Kitchen, John, Marion Kite, Pieter Hallebeek and Christopher Calnan. 1992. "The Restoration of Vellum and Silk from a Bugatti Chair." Conservation of Leathercraft and Related Objects: Interim Symposium at the Victoria & Albert Museum, 24th-25th June, 48-50.

Kowalik, Romuald. 1997. "Some Aspects of Microbiology of Paper and Parchment." In Das alte Buch als Aufgabe fur Naturwissenschaft und Forschung, edited by Dag-Ernst Petersen. Bremen-Wolfenbuttel (Wolfenbutteler Forschungen 1), 61-83.

Kozocsa, Ildikó. 1987. "Some Problems and Achievements in Codex Restoration in the National Széchényi Library." Conservation - Restoration of Leather and Wood: Training of Restorers, Sixth International Restorer Seminar, Veszprém (13-23 July, 1987). Budapest: UNESCO, 233-240.

Krivanek. F. 1991. "Conservation and Restoration of Parchment Charters and Wax Seals." 8th Seminar restauratoru a historiku.

Landsmann, A.W. 1991. "Lubricants." In Leather: Its composition and changes with, time, edited by C.Calnan & B.Haines. Northampton: The Leather Conservation Center, 29-33.

Langwell, William Herbert. 1957. The Conservation of Books and Documents. London 1957 (repr. London 1974 and 1977).

Laursen, Per M. 1985. "'Trockene' Pergament - und Papieranfaserung." Maltechnik Restauro 91(4): 63-66.

Lee, Linda. 1992. "The Conservation of Pleated Illuminated Vellum Leaves in the Ashmolean Bestiary." The Paper Conservator 16: 46-49.

Lee, Mary Wood. 1983. "Removal of Active Mold Growth and Treatment of Structural Damage in Nine Erotic Indian Miniatures." AIC Preprints. Baltimore, Maryland, 11th Annual Meeting: 140-149.

Lefevre, S. & C. Chahine. 1986. "Le nettoyage du parchemin." Les Documents Graphiques et Photographiques: Analyse et Conservation. Paris: Archives Nationales, 163-183.

Leighton, E. 1982. "News from the Paper Laboratory: Treatment of the Clevel and Museum of Art's Holy Family at Table by Ludovico Carracci." Inter-museum Conservation Association Newsletter 14: 5-8.

Lindsay, Jen. 1991. "A Limp Vellum Binding Sewn on Alum-tawed Thongs." The New Bookbinder: Journal of Designer Bookbinders 11: 3-19.

Logan, Judith A., and Gregory S. Young. 1987. "A Message in a Bottle: The Conservation of a Waterlogged Parchment Document." Journal of the International Institute for Conservation - Canadian Group 12: 28-36.

Lokanadam, B. and Chaudhury M. Ray. 1991. "Parchment in India: Some Observations". In Pergament, edited by Peter Rück. 315-22.

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Maggen, Michael. 1991. "Conservation of the Allepo Codex." Restaurator 12: 116-130.

Malkin, S. M. 1963. "The Week at Cooperstown: Editor's Comer." Antiquarian Bookman 32:4.

Marconi, Bohdan L. 1969. "Aesthetic Problems in Conservation of Art Objects on Paper and Parchment." ICOM Committee for Conservation, Proceedings of the Triennial Meeting, Paris.

Marconi, Bohdan L. 1962. "Some Tests on the Use of Wax for Fixing Flaking Faint on Illuminated Parchment." Studies in Conservation 7: 17-21.

Margotieva, Alla and Galena Bykova. 1991. "Materials and Methods of Conservation of Parchment Charters." Lecture presented in Jerusalem, November 1991.

Martin, John H. 1978. Après le Déluge ... Resuscitating a Water-logged Library." In Library Conservation: Preservation in Perspective, John P. Baker and Marguerite C. Soroka. Stroudsburg, PA: Dowden, Hutchinson & Ross, Inc., 391-399.

Martinek, F. 1988. Specific Problems of the Conservation and Restoration of the Czech Crown Archives, 7th Seminar restauratoru a historiku Kruzbcrk.

Martinovsky, Ivan. 1991. "Die neuesten tschecho- slowakischen Erfahrungen auf dem Gebiet der Pergamentrestaurierung." In Pergament, edited by Peter Rück. 247-52.

Matthews, Charles George. 1924. "Notes on the Treatment of Parchments Damaged by Fire." The Analyst 49: 516-517.

Maver, Ian. 1990. "Conserving the Records of the First Astronomer Royal." The Paper Conservator 14: 31-44.

Mecklenburg, Marion F. 1988. "The Effects of Atmospheric Moisture on the Mechanical Properties of Collagen Under Equilibrium Conditions." Conservation Analytical Laboratory-Smithsonian Institution, 231-244.

Michalski, Stefan. 1996. "Freezing Wood and Parchment." Paper Conservation News 80: 11-12.

Michalski, Stefan and Carole Dignard. "A New Method of Consolidating Powdery Matte Paint: The Ultrasonic Mister." Unpublished paper.

Middleton, Bernard C. 1984. The Restoration of Leather Bindings. Chicago: American Library Association.

Mokretsova, I.P. 1975. "Sur Quelques Particularités Technologiques et de la Restauration des deux Manuscrits Enluminés d'Europe Occidentale du XIIIe Siècle." ICOM Preprints of the 4th Triennal Meeting, Venice 1975. (#75/15/17): 1-10.

Mokretsova, I.P., Bykova, G.Z., Phinogenova, Y., and Serov, Y. 1978. "Treatment of a Greek Thirteenth Century Manuscript." ICOM Preprints of the 5th Triennial Meeting. Zagreb (#78/14/2): 1-8.

Mora, Paolo. 1968. "Il Restauro delle Miniature." Bollettino dell'-Istituto per la Patologia dell'Libro 27:113-115.

Mowery, J. Franklin. 1991. "The Conservation of a Thirteenth Century Armenian Manuscript." AIC Book and Paper Group Annual 10: 130-138.

Munn, Jesse. 1989. "Treatment Techniques for the Vellum Covered Furniture of Carlo Bugatti." AIC Book and Paper Annual 8: 27-38.

Murrell, Jim. 1972. "The Restoration of Portrait Miniatures." Conservation of Paintings and Graphic Arts IIC Lisbon Congress, 821-4.

NBS. 1951. "Preservation of the Declaration of Independence and the Constitution of the United States." NBS Circular 505. Washington, D.C.: National Bureau of Standards, 1-16.

1972. "A Note on the Conservation of Some Parchment Documents Damaged by Fire." Business Archives - The Journal of the Business Archives Council 33: 18-19.

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Ogden, Sherelyn (ed.). Preservation of Library and Archival Materials: A Manual. North East Document Conservation Center, North Andover, MA, 1992.

O'Hoski, Barbara. “Conservation of a Parchment Document,” Art Conservation Training Programs Conference. Newark: University of Delaware, 1976, pp. 64-76.

O'Loughlin, Elissa. “The Preservation of the Declaration of Independence,” National Archives Calendar of Events (July 1993).

Orlita, A. New Methods of Disinfecting Historic Documents by Butanol Vapors. 8th Seminar restauratoru a historiku (1991).

Ozone, Judy L. “Examination and Treatment of a Pair of 18th Century Battledores,” Student Papers Presented at the Art Conservation Training Programs, Eleventh Annual Conference, May 2-3, 1985, University of Delaware, Newark, pp. 79-84.

Paper Conservation Catalogue. Washington: Book and Paper Group of the American Institute for Conservation of Historic and Artistic Works.

Pardle, David Bernhard. Document Repair, London, 1971 (Society of Archivists, Handbooks 1).

Parker, A.E., “Freeze-drying of Vellum Archival Materials,” Journal of the Society of Archivists 14, no.2 (1993): 175-188.

Parker, Tony. “Freeze-Drying of Vellum,” Library Conservation News, 33, pp. 4-6.

Pedersen, Hans Peder. “Arkivvæsenets Pergamenter Bevaringsbestræbelser Gennem Tiderne,” Konservering og Restaurering af Læder, Skind og Pergament. Kompendium fra Nordisk Videreuddannelseskursus, 3-14 April 1978, Kulturer, Lund, Sverige. Copenhagen: Konservatorskolen Det Kongelige Danske Kunstakademi (1980): 348-357.

Pederson, Hans Peder. “(title unknown)”, Papers of the 18th International Congress of Paper Historians, Copenhagen, Denmark, 11-14 August 1986, IPH Yearbook 6 (1986).

Peterson, Dag-Ernst. "Notes on the Binding and Storage of Vellum-leaved Books", in Guy Petherbridge (ed.), The Conservation of Library ami Archive Materials and tile Graphic Arts. London: Butterworths (1987): 211-17.

Petukhova, Tatyana. “Potential Applications of Isinglass Adhesive for Paper Conservation,” The Book and Paper Group Annual 8 (1989): 58-61.

Petukhova, Tatyana and Stephen D. Bonadies, “Sturgeon Glue for Painting Consolidation in Russia,” Journal of the American Institute for Conservation 32, no.1 (1993): 23-31.

Plenderlith, H.J., and A.E.A. Werner. The Conservation of Antiquities and Works of Art. London: Oxford University Press, 1971.

Plossi, Mariagrazia Zappalà and Paolo Crisostomi. “Consolidation de la Couche Picturale des Enluminures avec Polymères Synthétiques Purs,” ICOM Preprints of the 6th Triennial Meeting Ottawa (1981) (81/14/7): 1-15.

Powell, Richard. Report on the Repair and Rebinding of the Cathach Together with Further Notes and Observations. Froxfield, August 1981.

Powell, Roger. “The Lichfield St. Chad's Gospels: Repair and Rebinding, 1961-1962,” The Library, Ser. 5, 20, no.4 (1965): 259-265, Figs.1-11 and Plates I-IX.

Powell, Roger. Report on the Repair and Rebinding of the Book of Kells. Froxfield, 1955.

Powell, Roger. “Case History of Repair and Rebinding of an Eighth-Century Vellum Manuscript.” In Philip Smith, (editor) New Directions in Bookbinding, London-New York, 1974, pp. 173-183.

Prosperi, Cecilia. “Il Restauro del Materiale Membranaceo,” Kermes 1, no. 3 September-December, (1988): 14-17.

Purinton, Nancy and Susan Filter. “Gore-Tex: An Introduction to the Materials and Treatments,” The Book and Paper Annual 11 (1992): 141-155.

Quandt, Abigail and Renee Wolcott. "The Codicology and Conservation of the Syriac Galen Palimpsest." Manuscript Studies: A Journal of the Schoenberg Institute for Manuscript Studies 3:1 (Spring 2018): 33-68.

Quandt, Abigail. “Recent Developments in the Conservation of Parchment Manuscripts”, The American Institute for Conservation, Volume 15, 1996. [Accessed 25th October 2015].

The article looks at the developments in the conservation of parchment; looking at media consolidation, humidification, and repair. The article describes different methods for consolidation of flaking paint on parchment, which can be done using a dilute solution (approximately 1%) of leaf gelatin, kept warm on a small hot plate or bain marie, or Klucel-G in ethanol can be used to stabilize the flaking paint that is water soluble, where ethanol is used to reduce the surface tension of the consolidant. The paper shows the different considerations one has to take when consolidating pigments: what the substrate is and what kind of pigment is deteriorating.

Quandt, Abigail. A l5th-century Italian Petrarch Manuscript from The Walters: Past and Present. Restoration (1996).

Quandt, Abigail, Parchment Conservation Course, Smithsonian Institution, Conservation Analytical Laboratory, Feb.1-5, 1993.

Quandt, Abigail B. “The Butler Hours: The Conservation and Rebinding of a Fourteenth Century English Book of Hours.” In Sheila Fairbrass, editor, Conference Papers Manchester 1992, The Institute of Paper Conservation, 1992, pp. 171-177.

Quandt, Abigail B. “The Documentation and Treatment of a Late 13th Century Copy of Isidore of Seville's Etymologies,” The Book and Paper Annual 10 (1991): 164-195.

Quandt, Abigail B. “The Conservation of a 12th Century Illuminated Manuscript on Vellum,” AIC Preprints 14th Annual Meeting (May 21-25, 1986): 97-113.

Quandt, Abigail and Sonja Fogle. "Leather Consolidation with Klucel G." Recent Advances ill Leather Conservation: Proceedings o f a Refresher Course. AIC (1985): 79-80.

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Ralston, Nicola L. "Parchment Conservation Placement at the J. Paul Getty Museum." SSCR Joumal 10:1 (1999): 18-19.

Reed, Ronald. "Some Thoughts on Parchment for Bookbinding", in P. Ruck (ed.), Pergament (1991): 217-20.

Reeves, M., A. Stenstrom and M. Sanchez-Posada de Arteni. "Aspects of Examination and Treatment of Parchment Materials, Part I: Design and Construction of a Magnetic Mount Microclimate System for the Towneley Lectionary Miniatures; Part 2: Notes on the Eighteenth-century Mapa de la Sierra Gorda in the New York Public Library Collections." lntemational Conference on Conservation and Restoration of Archive and Library Materials, Erice, 22-29 April (1996): 355-61.

Rennie, Silvia. "The Ascona Bookbinding Symposium, October 1982." The Abbey Newsletter 6 (1983): 75-6.

Ritterpusch, Ludwig. "Pergament-Restaurierung", in P. Ruck (ed.), Pergament (1991): 233-8.

Ritterpusch, Ludwig. “Konservierungsprobleme mit Pergament.” Konservering og Restaurering af Læder, Skind og Pergament Kompendium fra Nordisk Videreuddannelseskursus, 3-14 April 1978, Kulturer, Lund, Sverige. Copenhagen: Konservatorskolen Det Kongelige Danske Kunstakademi (1980): 337-347.

Ritterpusch, Ludwig. “Konservierung und Restaurierung von Bucheinbänden aus Leder und Pergament,” Konservering og Restaurering af Læder, Skind og Pergament Kompendium fra Nordisk Videreuddannelseskursus, 3-14 April 1978, Kulturer, Lund, Sverige. Copenhagen: Konservatorskolen Det Kongelige Danske Kunstakademi (1980): 294-299.

Rosa, Halina and A. B. Strzelwyk. "Parchment: Report on Conservation and Scientific Methods Developed in the Laboratory of Paper and Leather Conservation at the Nicolaus Copernicus University, Torun, Poland", in P. Ruck (ed.), Pergament (1991): 248-52.

Rosa, Halina. “Problems of Parchment Conservation Dealing with the Pages of Wittenbergia Bible,” International Conference of Experts of Eastern European Countries on the Care and Conservation of Library Collections, Warsaw, 1987.

Rouy, Dominique and Claire Chahine. “Elimination des Taches sur le Parchemin a l'aide de Peroxyde d'Hydrogene: Premiers Resultats,” ICOM Committee for Conservation, Preprints for 10th Triennial Meeting, Washington, D.C. 22-27 August 1993: 474-478.

Schack, Marliese and Michael Fackelmann. "A Note on Practical Work carried out at the Austrian Nutional Library's Institute for Book Restoration using New and Newly Adapted Methods." Internatlonale Arbeitsgemeinschaft der Archiv-, Bibliotheks- und Graphik-restauratoren Berlin, 5-9 October (1987): 8.

Scharnowell, Norbert. “Evangelien handschrift Cod. 93 in Scrinio,” Restauro 1 (1991): 35-39.

Schmitzer, Werner. "Pergament: Das Material fuer Schattenspielfiguren, ihre Herstellung und ihre Restaurierung", in P. Ruck (ed.), Pergament (1991): 323-40.

Shelley, Marjorie. “Old Master Drawings: An Approach to Conservation,” The Book and Paper Annual 8 (1989): 62-66.

Sievers, Johannes. “Fehlstellenergänzung bei Pergament durch Anfasern,” Maltechnik Restauro 3 July (1979): 209ff.

Singer, Hannah. “The Conservation of Parchment Objects Using Gore-Tex Laminates,” The Paper Conservator, 16 (1992): pp. 40-45.

Skordas, Gust. “The Parchment Stretcher at the Maryland Hall of Records,” The American Archivist 3 (1940): 330-332.

Smith, L. Herman. “Manuscript Repair in European Archives: Part I Great Britain,” The American Archivist 1, no. 2 April (1938): 1-22.

Smith, L. Herman. “Manuscript Repair in European Archives: Part II The Continent,” The American Archivist 1, no. 2 April (1938): 51-77.

Snizek, L. and J. Hejzlarova. Restoration of Badly Damaged Charters from the Collection of the Czech Crown Archives, 8th Seminar restauratoru a historiku (1991).

Stachelberger, H., G. Banik and A. Haberditzl, "Naturwissenschaftliche Untersuchungen zum Pergament: Methoden und Probleme", in P. Ruck (ed.), Pergament (1991): 183-94.

Stambolov, Todor. “The Conservation and Restoration of Gilt Leather,” Konservering og Restaurering af Læder, Skind og Pergament Kompendium fra Nordisk Videreuddannelseskursus, 3-14 April 1978, Kulturer, Lund, Sverige. Copenhagen: Konservatorskolen Det Kongelige Danske Kunstakademi (1980): 309-313.

Stankiewicz, J., "The Conservation of Hebrew Manuscript No. 80 2238 in the Jewish National and University Library, Jerusalem: An Evaluation of the Method." Restaurateur 17:2 (1996): 64-74.

Straka, R. The Storage of the Czech Crown Archives, 7th Seminar restauratoru a historiku, Kruzberk (1988).

Sully, D.M., “Humidification: The Reshaping of Leather, Skin and Gut Objects for Display,” Conservation of Leathercraft and Related objects: Interim Symposium, ICOM Committee for Conservation (1992) pp.50-54.

Szczepanowska, Hanna. “The Conservation of 14th Century Parchment Documents and Pendant Seals,” The Paper Conservator, 16 (1992): pp. 86-92.

Szlabey, Gyorgyi. “Restoration of Corvina Cod. Lat.3.” In Beatrix Kastaly, editor, Papers of the Conference on Book and Paper Conservation held in Budapest 4-7 September 1990, Budapest: Technical Association of Paper and Printing Industry and the National Szechenyi Library (1992), pp.576-599.

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Tanasi, Maria T., Giancarlo Impagliazzo and Daniele Ruggiero. "Une approche preliminaire it la caracterisation du parchemin", in P. Ruck (ed.), Pergament (1991): 203-16.

Tanasi, M.T. et al. “Messa a punto di una metodologia relative al restauro di pergamene dell'archivio comunale di Matelica,” Le Conservazione delle carte antiche, 4, no.7-8 (1984): pp.21-26.

Tribolet, Harold W. "'All the King's Horses': Rare Book and Manuscript Preservation Techniques." History News: Technical Leaflet 18 (1963).

Turner, Nancy, “The Conservation of Medieval Manuscript Illuminations and the Question of Compensation, WAAC Newsletter 16, no.1 (January 1994): 21-22.

“Unrolling of the Dead Sea Scrolls,” New Scientist 88, (1980): p. 365.

Valk-Falk, Endel. “Technique et Conservation des Reliures Gréco-Slav,” ICOM Preprints of the 4th Triennal Meeting, Venice (1975): (15/1/15): 1-7.

van Soest, H.A.B. “The Restoration and Conservation of Ethnographical Leather,” Konservering og Restaurering af Læder, Skind og Pergament Kompendium fra Nordisk Videreuddannelseskursus, 3-14 April 1978, Kulturer, Lund, Sverige. Copenhagen: Konservatorskolen Det Kongelige Danske Kunstakademi (1980): 300-307.

Van Soest, H.A.B. “Researching the Conservation and Restoration of Parchment,” ICOM Arbeitsgruppe, Leathercraft and Related Objects, International Learner- and Parchmentsymposium, 8-12 May, 1989: 94-103.

Victoria and Albert Museum Conservation Department. The Care of Portrait Miniatures. Victoria and Albert Museum, London, 1970.

Vinas Torner, V. “El polietilenglicol: tratamiento para la establizacion de libros y documentos”, Centro Nacional de restauracion de libros y documentos, 2 (1979): 25-33.

Vinas, Vicente. “Parchment and Vellum Restoration: Treatment and Stabilization,” Conservation Administration: Seminar on the Theoretical Aspects of the Conservation of Library and Archival Materials. R. Morrison et al. (editor). North East Document Conservation Center (pub.) North Andover, Massachusetts (1975): 108-114.

Vinas, Vicente. “The Use of Polyethylene Glycol in the Restoration of Parchment.” In Guy Petherbridge, editor. Conservation of Library and Archive Materials and the Graphic Arts. London-Boston, 1987 (Proceedings of the Cambridge 1980 International Conference on Conservation), pp. 195-197.

Vitkus, John R. and John F. Asmus. "Treatment of Leather and Vellum with Transient Heating." Preprints of the 4th AIC Conference, Dearborn (1976): 111-17.

Vodopivec, Jedert. 'The Preservation and Protection of Medieval Parchment Charters in Slovenia', in IADA Preprints 1995, ed. Mogens S. Koch and K. Jonas Palm (Copenhagen: Royal Danish Academy of Fine Arts, 1995), pp. 39-43.

Though this article primarily focuses on the preservation of parchment, it also describes the deterioration of wax and metal seals which are found with parchment. Parchment needs to be kept in a stable environment, as it is highly susceptible to changes in humidity. The most common material used to make seals in the Middle Ages was natural or coloured beeswax, and metals such as lead, were used occasionally as well. Coloured waxes were introduced in the 12th century, first red was used, and then green, black and dark blue. In Slovenic territories, the wax seals remained uncoloured until the 14th century. The chemical composition of uncoloured waxes varies, while the composition of coloured seals never changes. Coloured waxes don’t usually display signs of deterioration and remain very stable upon ageing.

Voronina, L.I., Nazarova, O.N., Petushkova, Yu.P. “Disinfection and Straightening of Parchment damaged by Microorganisms,” in: Restaurator, 4, (1980): 91-97.

Voronina, L.I.; Nazarva, O.N.; Petushkova, U.P. and N.L. Rebrikova. “Damage of Parchment and Leather Caused by Microbes,” ICOM Preprints of the 6th Triennial Meeting Ottawa (1981): (81/19/3): 1-11.

Vuori, Jan, “A Possible Adhesive for Native Tanned Skin,” Leather Conservation News 2, no.1 (1985):6.

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Wachter, Otto."Das Pergament als Bildtraeger. Der konservatorische Aspekt", in P. Ruck (ed.), Pergament (1991): 279-98.

Wachter, Otto. “Diagnosis and Therapy in Parchment and Miniature Restoration,” originally published in Restaurator 5, nos. 1&2 (1981-82): 135-150. English translation by Nancy A. Miller, edited by Jack C. Thompson, The Caber Press, 1987.

Wächter, Otto. “Die De-Laminierung des karolingischen Evangeliars aus dem Essener Domschatz,” Maltechnik Restauro 93, no. 2 (1987): 34-38.

Wächter, Otto. “Die Restaurierung einer Armenischen Evangelien-Handschrift (Cod. 242) aus der Bibliothek der Mechitaristen-Congregation in Wien,” Österreichische Zeitschrift für Kunst und Denkmalpflege 22 (168): 43-47.

Wachter, Otto. “The restoration of the “Vienna Dioscurides'.” Studies in Conservation, vol.7 (1962): 22-26.

Wachter, Otto. Restaurierung und Erhaltung von Buchern, Archivalien und Graphiken. Vienna, Austria: Hermann Bohlaus Nachf, 1982.

Wachter, Otto. “Tour of the Conservation Laboratory, National Library of Austria.” In Merrily A. Smith, editor. Preservation of Library Materials, Conference held at the National Library of Austria, Vienna, April 7-10, 1986, volume 2, Munich-London-New York-Paris, 1987 (IFLA-Publications 41), pp. 92-97.

Wächter, Wolfgang. "Pergament: Die gegenwaertig praktizierten restauratorischen Methoden und ihre Beziehung zum Erkenntnisstand", in P. Ruck (ed.), Pergament (1991): 229-32.

Walters Art Gallery. "Conservation and Technical Research", 37th Annual Report of the Walters Art Gallery for the Year 1969 (1970): 24-7.

Waters, Peter. "In Search of a New Philosophy of Conservation and Restoration." The Guild of Book Workers Journal 7 (1968): 12-21.

Weidner, Marilyn Kemp. “Treatment of Water Sensitive and Friable Media using Suction and Ultrasonic Mist,” The Book and Paper Annual 12 (1993): 75-84.

Weidner, Marilyn Kemp. “Water Treatments and their Uses within a Moisture Chamber on the Suction Table,” AIC Preprints, Washington, D.C. (May 1985): 127-140.

Welsh, Elizabeth C. “A Consolidation Treatment for Powdery Matte Paint,” AIC Preprints. San Francisco, 8th Annual Meeting (1980): 141-150.

Werner, A.E. “The Conservation of Leather, Wood, Bone, Ivory, and Archival Materials,” The Conservation of Cultural Property with Special Reference to Tropical Conditions, Paris: UNESCO, 1968 pp. 265-290.

Werner, A.E. “Restoration of Manuscripts and Archival Documents,” Collogues Internationaux du C.N.R.S. 1974. no. 548: Les Techniques de Laboratoire dans l'Étude des Manuscrits, pp. 257-260.

Whitfield, Lynn, Tom Bryce and Jim Tate. "The Treatment of Composite Objects." The Laboratories of the National Museum of Antiquities of Scotland (1980): 61-4.

Wolbers, Richard C., Nanette T. Sterman and Chris Stavroudis. Notes for Workshop on New Methods in the Cleaning of Paintings. Los Angeles, California: The Getty Conservation Insitute, 1990.

Wo_niak, Maria. “Zur Restaurierung eines Illuminierten Pergamentmanuskriptes aus dem 18. Jahrhundert,” Restauro 4 (1990): 295-301.

Wouters, Jan and Gely Gancedo. The Codex Eyckensis. An Illuminated Manuscript on Parchment from the 8th Century AD. Laboratory Investigation and Removal of a 30 year-old PVC Lamination,” ICOM Preprints of the 9th Triennial Meeting, Dresden, Germany, August (1990):. 495-499.

Wouters, Jan, Gely Gancedo, An Peckstadt and Lieve Watteeuw. “The Conservation of Codex Eyckensis: The Evolution of the Project and the Assessment of Materials and Adhesives for the Repair of Parchment,” The Paper Conservator, 16 (1992): 67-77.

Wouters, Jan, Gely Gancedo, An Peckstadt and Lieve Watteeuw, “Parchment Leafcasting with Dermal Tissue Preparations,” ICOM Committee for Conservation, Preprints for 10th Triennial Meeting, Washington, D.C. 22-27 August 1993:524-528.

Young, Pamela. “Parchment and Its Conservation,” Conference of Students in Art Conservation April 10-12, 1978 Cooperstown, New York pp. 156-164.

Yusupova, M.V. “Conservation and Restoration of Manuscripts and Bindings on Parchment,” Restaurator 4, no. 1 (1980): 57-69.

Yusupova, M.V. “Removal of General Soils and Pigment Spots from Parchments,” ICOM Preprints of the 5th Triennial Meeting, Zagreb (1978) (78/14/11): 1-4.

Yusupova, M.V. “Removal of Transparency of Manuscripts and Documents on Parchment,” ICOM Preprints of the 7th Triennial Meeting, Ottowa, (1981) (81/14/13): 1-5.

Zelinger, J. Konzervace pergamenu a jeho ulozeni, NK CR, Prague, 1992.

Materials for Parchment Treatment

Tools and Equipment

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General Cleaning and Removal of Old Repairs and Mounts

• Optivisor, Magnifier or Binocular microscope
• Kneaded Eraser, Groom Stick and/ or Vacuum Aspirator (for mold removal)
• Vinyl Eraser - Block or Crumbs
• Crepeline Eraser
• Electric Eraser with Vinyl Tip
• Microspatulas, Teflon Spatula, Casselli Knife
• Scalpels
• Soft Brush
• Tweezers
• Spun-bonded Polyester, Blotters, Gore-Tex Polyester Web Laminates
• Preservation Pencil (available from University Products)
• Ultrasonic Humidifier With Hose/Nozzle Attachments

Consolidation

• Fine Sable Brushes (00 or 000)
• Bamboo Skewer with Bevelled Edge, Teflon Spatula or Spoon Shaped Dental Tool (for setting down lifting flakes of paint and ink) Bone Folder, Teflon Folder
• Silicon Release Paper or Silicon-coated Mylar (as interleaf for setting down paint flakes)
• Binocular Microscope with Fiber Optic Light
• Regular or External Mix Air Brush and Compressor
• Vacuum Suction Table
• “Ultrasonic Mister”

Humidification

• Blotters, Polyester Web, Pressing Boards or Thick Plexiglas (with everything cut to same dimensions for damp blotter pack)
• Gore-Tex Polyester Web Laminates
• Spun-bonded Polyester (Hollytex, Remay)
• Blotters
• Photo Trays, Screens and Plexiglas (for simple humidity chambers)
• Sodium Chloride (for saturated salt solutions to maintain humidity levels inside chambers)
• Ultrasonic Humidifier with Hose and Nozzle Attachments
• Plexiglas Dome or Box
• Ready-made Humidity Chamber (Weidner, Lascaux, etc. available from Museum Services Corp.)
• Air Brush and Compressor (for spray humidification)
• Humidity Indicator Strips or Hygrometers
• Moisture Meter (Aqua Boy, Sovraign, or Digital Mini Protimeter)

Tensioning/Drying

• Bulldog Clips - jaws padded and made parallel with Ethafoam, thick blotters, or matboard
• Pins - dissecting pins or home-made pins with wooden dowel and bookbinding needles
• Insulation Board (Homasote), Ethafoam or Plywood (for pinning out parchment)
• Lead Sinkers and Heavy Thread (for tensioning weights)
• Plexi or Glass Strips (for tensioning at edges)
• Tensioning Frame (See Smith and Bunting 1993.)
• Vacuum Suction Table
• Polyethylene, Polyester Film or Rubber Dam Material (for masking off suction table)
• Thick Wool Felts (preferable to woven papermaker's felts)
• Spun-bonded Polyester, Blotters (with smooth finish)
• Gore-Tex Polyester Web Laminates
• Pressing Boards - thick plexi or glass sheets or formica-covered board
• Weights (of various sizes and dimensions)
• Bookbinding Press (“Nipping Press”)
• Moisture Meter (Aqua Boy, Sovraign, or Digital Mini Protimeter)
• Electric Timer (for monitoring length of humidification treatments)

Repair

• Sanding Sticks - wooden dowel and/ or wooden swab sticks covered with sandpaper of various grit sizes
• Wooden Block with Rounded Edges (to support parchment fill while sanding edges)
• Small Paring Knives (for bevelling edges of parchment fills)
• Swivel Knife (for cutting out intricately shaped pieces of transparent membrane)
• Scalpels
• Flexible Shaft Drill with Abrasive Bits (Fordom, Dremel)
• Bone Folders, Teflon Folders
• Tweezers
• Brushes
• Blotters, Polyester Web (small pieces)
• Plexiglas or Glass Strips and Weights
• Light Box with Cool Surface
• Photo Trays or Air Brush and Compressor (for toning parchment and paper)
• Vacuum Suction Table (for pulp fills)
• Atomizer, Blender, Eye Dropper, Flexible Plastic Bottle, Polyethylene (for masking around area of loss)
• Ultrasonic Humidifier With Hose/Nozzle Attachment
• Diolen (fine silk fabric similar to crepeline)

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Adhesives

See Historic Adhesives and Consolidants for adhesives no longer used in parchment treatments.

Collagen-Based Adhesives

Gelatin

General Information: Gelatin is used both as an adhesive and a consolidant for the conservation of parchment. Food grade gelatin is available commercially in sheet form (known as edible leaf gelatin) and also in powdered or granulated form. More highly purified pharmaceutical grade and “photographic quality” gelatins are available in granulated form from Eastman Kodak and Fisher Scientific. Gelatins are graded by viscosity in millipoises and jelly value in Bloom grams. The lower the Bloom number, the weaker the gel. (See Adhesives: Proteinaceous Adhesives: Collagens: General Information: Chemical and Physical Properties) Solutions of gelatin are quick to prepare and the actual concentration of gelatin in solution is easily documented. For these reasons gelatin is often preferred over parchment size by many conservators.

Preparation: Leaf, powdered or granulated gelatin are all prepared in a similar way by swelling the adhesive in cold water for an hour or more, and then heating it at approximately 50°C until it goes into solution. In the past, painters and restorers have used such additives as common salt, urine, calcium chloride, zinc chloride, magnesium chloride, herring brine, etc., to alter the hardening (i.e., resulting flexibility) of gelatin (see Wehlte 1975, p.374).

Use: Gelatin must be kept warm in a double boiler so that it stays liquid during use. It can be applied directly with a brush or used in a dilute form in a spray gun or air brush. In the past Anthony Cains has included additives such as sorbitol (a humectant which, in theory, keeps the adhesive flexible upon drying) and small quantities of dilute acetic acid to gelatin when it was used as an adhesive (Cains 1982/83, p.22.) However, this practice has long been discontinued by Cains because the additives seemed to have little effect; controlling the film thickness of the adhesive produced better results. (AC) In order to achieve greater penetration during consolidation treatments it is common to add either ethanol or isopropanol directly to a dilute solution of gelatin or to apply the alcohol in a separate step to the area being consolidated.

Storage: Refrigeration will prolong the shelf life of a gelatin solution for approximately one month. For long-term storage liquid gelatin can be dried or frozen (see description of parchment size above), yet this is rarely done because fresh solutions are easily prepared from the commercial product.

Caveats: Similar to those associated with parchment size. Gelatin solutions can often be more yellow in color yet they possess a similar tack to solutions of parchment size. Gelatin solutions will tend to be more acidic (pH 4–5) and even more so if acetic acid is added.

Isinglass (Sturgeon Glue)

General Information: Sturgeon glue has a long history of use in Eastern Europe as a consolidant and an adhesive in both painting and paper conservation. In contrast to fish glue, which is made from the head, skin and bones of fish, isinglass is prepared from the inner membrane of the air or swim bladder of the sturgeon. Russian isinglass, prepared from two specific types of sturgeon, is considered to be the superior product compared to other types of isinglass. (See discussion of types of fish used to manufacture “Russian Isinglass”, Alexander.) Sturgeon glue is also said to have a lower viscosity and greater tack than other collagen-based adhesives (see discussion of surface tension in Bogue 1922, p.115), such as gelatin or parchment size, and its lower gelation temperature is also advantageous in certain situations when high heat cannot be employed. Certain varieties of isinglass (yet not the Russian type) are sold by Kremer Pigments in New York and Germany and by Cornellisen in London.

Preparation: According to Petukhova and Bonadies (1993, p.23) “Sturgeon glue is made by washing the fish bladders in hot water to remove extraneous material. The bladders are then cut open to expose the inner membrane to the air. When almost dry, the outer membrane is removed by rubbing and beating.” The dried inner membrane, which is usually sold in either thick sheets or as thin, narrow strips, is allowed to soak and swell in water for several hours. The water is decanted and fresh water is added to the swollen glue in a double boiler. The glue is gently cooked at a low temperature (no greater than 60°C) until the membrane dissolves. The solution is strained if necessary prior to use.

Use: Although information about the use of isinglass for the conservation of parchment artifacts is not readily available, it has been recently suggested as a possible consolidant for flaking paint on parchment supports. (See Petukova and Bonadies 1993, p.29.) Since isinglass will gel upon cooling it needs to be kept warm in a double boiler during use. It is most often applied with a brush, yet can also be used in spray form for consolidation purposes. A repair tissue coated with isinglass (the manufacture of which is described by Petukhova 1989) has been recently used for semi-transparent mends on parchment (see Mending and Filling). Honey has traditionally been added to solutions of isinglass for use in painting conservation, and other plasticizers such as glycerin and propylene glycol have been suggested as possible substitutes. However, the long-tern effects of these additives have not yet been thoroughly investigated. (See Petukhova and Bonadies 1993, p.24.)

Storage: The stock solution of isinglass can be kept for several days if refrigerated. For long-term storage solutions of isinglass can presumably be dried or frozen, but this is usually unnecessary since the adhesive is easily prepared from the dried commercial product.

Caveats: The purest type of isinglass is manufactured in the former Soviet Republic and is therefore difficult to obtain in the West. It is very hygroscopic and even more so for products made from insufficiently washed raw materials that contain much sodium chloride. Sturgeon glue is also susceptible to attack by insects and mold in conditions of high relative humidity. It can also become brittle under very dry storage conditions.

Cellulose-Based Adhesives

Wheat Starch Paste

General Information: In parchment conservation wheat and rice starch pastes have been used primarily as adhesives; they are generally considered too viscous for use in consolidation. (See Mending and Filling.) Starches derive from a variety of plant sources including corn, potatoes, rice and wheat, yet all are polysaccharides that are made up of two basic components: amylose and amylo-pectin. Wheat starch generally has a higher percentage of amylose (17–27%) than rice starch.

Preparation: Many recipes for the preparation of rice or wheat starch paste have been published in the conservation literature. In general the dry powder is soaked in water and then cooked at a moderate temperature with constant stirring. During the cooking process the granules of amylose and amylopectin swell and burst, forming a sticky paste. After cooking the paste is strained and then diluted with water for use. Wheat and rice starch are currently available from many conservation suppliers including Talas, Conservation Materials, University Products and others.

Use: Wheat starch paste is currently used with Japanese paper and also with new parchment for the repair of damaged parchment manuscripts and documents. It can also be used with goldbeater's skin or fish skin yet the mend is not often as strong or transparent as when gelatin or parchment size are employed. In a recent series of tests on a variety of adhesives being evaluated for use in parchment repair wheat starch paste performed very well (see Wouters et. al., 1992).

Rice starch paste is generally considered to produce a smoother and stronger but more brittle adhesive than wheat starch paste (See Adhesives: Rice Starch Paste). Although not as widely used for repair as wheat starch paste, rice starch tends to be preferred by many book conservators for certain specific applications.

Caveats: Starch films shrink upon drying and can continue to lose moisture and shrink over time, especially in conditions of low relative humidity. Starch films do not seem to adhere well to a smooth surfaced parchment. Aged starch films can sometimes be difficult to reverse, although this presents a greater problem when applied to a weak degraded parchment than a healthy one.

• Cellulose Ethers

General Information: Cellulose ethers are made from wood pulp or cotton linters that are swollen and decrystallized using sodium hydroxide. The “alkali” cellulose undergoes etherification or methylation in order to partially substitute the hydroxyl groups on the anhydroglucose ring with alkyl or hydroxyalkyl groups such as methyl, ethyl, sodium carboxymethyl, hydroxyethyl or hydroxypropyl. After neutralization with acids the cellulose ether is further purified and then dried, milled and sifted. Cellulose ethers are produced by many companies in various grades, viscosities and degrees of polymerization (DP). The best products are the highly purified varieties made for adhesive applications.

Preparation: Most cellulose ethers are soluble in cold water. Sodium carboxymethyl cellulose and hydroxyethyl cellulose are also soluble in hot water. Only hydroxy-propyl, ethyl hydroxyethyl cellulose, and ethyl cellulose are initially soluble in polar organic solvents. Although clumping usually occurs upon adding the dry powder to the solvent the cellulose ether eventually goes into solution, especially if stirred regularly.

Use: Cellulose ethers are generally not strong enough to be used on their own as adhesives for the repair of healthy parchment, but they often work well for the consolidation of friable or flaking media and for the consolidation and repair of weak or degraded parchment. In these situations the adhesive is usually applied with a brush. Cellulose ethers can also be mixed with other adhesives, to alter or improve their working characteristics.

Methyl Cellulose: Methyl cellulose is produced by several American and European companies under different trade names. Dow Chemical produces Methocel; Culminal, produced by Henkel in Germany, is sold in the U.S. by Process Materials or Archivart who attaches their own name to the product. A roughly 1–2% solution of methyl cellulose in water and ethanol is sometimes used as a consolidant for powdery matte paint in illuminated manuscripts (A.Q.). A methyl cellulose with a high degree of polymerization, dissolved in 80/20 methylene chloride/ methanol, has been used for ink consolidation on parchment in Italy. (See Consolidation of Media.)

Hydroxypropyl Cellulose: This cellulose ether is manufactured by the U.S.-based Hercules Corporation who labels their product Klucel. A 2–5% solution of Klucel-G in ethanol is used by Anthony Cains for the local sizing of degraded parchment prior to repair. (See Consolidation of Degraded Parchment.) Klucel-G in ethanol is also used for media consolidation on parchment in several European countries. (See Consolidation of Media.) Repair tissues coated with more viscous solutions of Klucel-G or Klucel-J in ethanol have recently been used for the repair of weak, degraded parchment. (See Mending and Filling.)

Methyl Hydroxyethyl Cellulose: This cellulose ether is made by Hoechst in Germany under the trade name of Tylose. It is widely used in Europe for both paper and parchment conservation. Tylose MH300 is currently used in Italy, either on its own or mixed with 5% Vinavil, a polyvinyl acetate emulsion, for the repair of parchment documents. Tylose MH300 was also recently selected as a suspension agent for the leafcasting of a severely damaged medieval manuscript using a purified hide powder (see Wouters, et al. 1992).

Storage: Cellulose ethers are remarkably resistant to mold growth, lasting months unrefrigerated, though ultimately they will attract mold growth. Refrigeration is best for the storage of cellulose ether solutions. The powder should be kept dry, in a tightly sealed container, and away from light.

Caveats: In a recent study by Robert Feller several cellulose ethers including hydroxypropyl cellulose did not perform well under artificial aging. (See Feller 1992.) Although methyl hydroxyethyl cellulose (Tylose) was not included in this particular study, tests in 1984 showed that it yellowed only slightly under artificial aging conditions. (See Adhesives: Methyl Hydroxyethyl Cellulose (MHC).)

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Synthetic Polymers

• Polyvinyl Acetate Dispersions

General Information: Poly vinyl acetate dispersions, which are often incorrectly referred to as emulsions, are made by suspending minute particles of PVA resin in water. PVA dispersions can either be homopolymers or copolymers. Homopolymers require the addition of an external plasticizer, which make them susceptible to embrittlement, discoloration, insolubility and staining. Copolymers do not have these same problems since the comonomer acts as an internal plasticizer, and thus has a stabilizing effect on the adhesive. Many commercial grades of PVA dispersions are available, made by 40–50 different manufacturers. Products currently used in conservation include Jade 403 (Jade Adhesives), Elvace (Reinhold Chemicals), Conservation Materials CM-Bond series, Adhesin A22 (Henkel, Dusseldorf, Germany) and numerous other brands.

PVA is a film building adhesive and tends to sit on the surface to which it is applied. It is thus more likely to be reversed with water or polar solvents than other adhesives that penetrate more into the support.(JFM)

Preparation: PVA dispersions are sold as a white viscous liquid. They can be used as is or diluted with water to the desired viscosity. For certain applications one can mix PVA dispersions with other adhesives such as starch paste or methyl cellulose, in order to change the working properties of the material. Although PVA dispersions may sometimes be diluted with organic solvents for the consolidation of unstable media on paper supports this has not yet been done on parchment. (See Consolidation, Fixing, and Facing: Synthetic Adhesive Dispersions.)

Use: Described by Giuffrida (1983) for adhering parchment patches over losses in manuscripts. It is currently used in Italy and Germany for parchment repair.

The PVAc, (Adhesin A22, made by Henlke, Dusseldorf) has been tested for use in conservation by Dr. Halmut Bansa in a comparison with other German products. This research has been corroborated by Dr. Robert Fuchs, head of the conservation school in Koln. Currently, this specific adhesive is used in the lab of Dag-Ernst Petersen (Herzog August Bibliothek Wolfenbuttel). The same adhesive has also been used for book restoration at the Bavarian States Library, Munich since the end of World War H. In correspondence, Mr. Petersen writes that “under certain circum-stances, when it is necessary to build a long lasting, flexible and reversible connection Adhesin A22 is used. In order to avoid the splitting off of acid a mixture of two-thirds A22 and one-third CMC is made.”

A dilute solution of JADE 403 was recently used to prepare and attach laminates of Japanese paper and goldbeater's skin to the damaged parchment leaves of an Armenian manuscript. (Mowery 1991, pp. 135–136.) Book conservators sometimes use PVA dispersions for certain specific applications, such as in the repair of vellum bindings, where the adhesive's strength and flexibility are desirable features. Combinations of PVA and Klucel-G in ethanol can be used to make Japanese paper repairs more transparent. (See Mending and Filling.)

Caveats: PVA dispersions will gradually release acetic acid over time and therefore their recommended shelf life is limited to 9–12 months. Dispersions are susceptible to damage by temperatures less than 4.44°C (40°F). They can also support mold growth. Additives may dramatically affect the aging characteristics of many PVA dispersions and these may be subject to change by the manufacturers at any time. The reversibility of PVA dispersions is often problematic, largely due to their increased insolubility with age. (See Adhesives: Poly Vinyl Acetate Dispersions (PVA) for further information on aging characteristics, etc.) Tests carried out on Mowolith DM5, a PVA dispersion made by Hoechst in Germany, proved it to be unsuitable for use in the repair of parchment. (See Wouters, et. al. 1992.) The undesirable attraction of dust and the blocking of adjacent leaves has been observed on parchment manuscripts that were repaired in the past with an externally plasticized PVA emulsion. (See Cains 1982/83, p.18.)

PVA dispersions vary greatly, and some have better ageing properties than others. In a recent study of poly(vinyl)acetate and acrylic adhesives undertaken at the Canadian Conservation Institute, which used natural instead of artificial aging, JADE 403 performed very well. However, reversibility studies were not performed as part of this project. (See Down, et. al. 1992.)

• Acrylic Resin Solutions

General Information: Acrylic resins were developed for industrial use in 1931. The n-butyl and isobutyl methacrylates are the acrylic polymers in longest use in conservation, with some of the earliest testing having been done at the Fogg Art Museum in the 1930's. Acrylic resins are addition polymers of acrylic and methacrylic acid and their esters. Rohm and Haas, Philadelphia, manufactures a variety of acrylic resins under the trade name Acryloid (called Paraloid in Europe). Although many other acrylic resins are manufactured by different companies, the Acryloid series has found the widest use in the conservation of parchment and other untanned or semi-tanned materials. Acrylic resin solutions are strong, durable adhesives with excellent flexibility characteristics.

Preparation: Acryloid B-72, a 70% ethyl methacrylate, 30% methyl acrylate copolymer, is available as colorless beads of resin or as a 50% solids solution in toluene. B-72 is unique among acrylic resins in having a high tolerance for ethanol and it is frequently dissolved in this solvent when used in parchment conservation. It is also soluble in several other organic solvents, including toluene, xylene, acetone, MEK, ethyl acetate and amyl acetate. B-72 is insoluble in isopropanol. Acryloid B-48, a methyl methacrylate copolymer, has also been used on occasion for the conservation of non-tanned skin materials. Solutions of acrylic resins are prepared by suspending the beads in a cheesecloth bag inside a container of solvent for 24 hours or more. Sometimes a magnetic stirrer can be useful for speeding up the dissolution of the resin in the solvent.

Use: Acryloid B-72 is currently used in Italy for the consolidation of flaking and friable media on parchment. B-72 is used in Madrid to stabilize media on parchment manuscripts and documents prior to immersion in a bath of polyethylene glycol. (See Vinas 1987.) A tissue coated with an 18% solution of B-72 in toluene was used in 1985 at the Turin Archives, Italy, for the lamination of a perforated parchment document. In this case the adhesive was activated with heat. A mixture of Acryloid B-72 and EHEC (an ethyl hydroxyethyl cellulose manufactured by Hercules) has recently been used for the repair of ethnographic skin objects (see Vuori 1985, and Dignard 1992) and might also be applicable to parchment repair. (JS) A solution of Acryloid B-48N in toluene has been applied to small pieces of goldbeater's skin, which were then used to repair tears in bird skin. In this case the adhesive was activated with toluene (see Kaminitz and Levinson 1988).

Caveats: According to Feller (1971), Acryloid B-72 is the most reversible of the acrylic adhesives; it remains soluble and does not cross-link significantly upon aging. Other acrylic resins, such as Acryloid B-48, tend to cross-link through heat and ultra-violet and visible light exposure. They generally remain colorless and transparent over time. In recent tests, solutions of Acryloid B-72 in ethanol and in diacetone alcohol were rejected as adhesives for parchment repair because of their poor water vapor permeability and because of the surface damage that was caused in attempting to reverse parchment to parchment joins that had been executed using B-72. (see Wouters, et. al. 1992).

• Acrylic Resin Dispersions

General Information: Acrylic resin dispersions were formulated in 1953 for use as painting media by artists and for industry. Acrylic dispersions are prepared by emulsion polymerization. Those currently used in conservation are copolymers of acrylic resins: blends of ethyl acrylate and methyl methacrylate made from monomers of methyl, butyl, and other longer chain esters of acrylic or methacrylic acids. Although many different acrylic resin dispersions are currently available, the Rhoplex series made by Rohm and Haas, Philadelphia, are the only ones that have been used to date for the treatment of parchment. The Plextol series, made by Rohm Gmbh in Germany, are widely used in Europe but are not considered to be a direct substitute for the Rhoplex resins. (See Adhesives: Acrylic Resin Dispersions.)

Preparation: Acrylic resin dispersions are sold as a milky white liquid of resin solids dispersed in water. They can be used as is or diluted with water or organic solvents. In the manufacture of Library of Congress heat-set tissue Rhoplex AC-234 and AC-73 are mixed together and painted out on glass. Lens tissue is dropped in place on the wet adhesive and allowed to air dry. (The method used at Trinity College Library, Dublin is the same except the adhesive formula is one part Plextol M630 and two parts Plextol B500, diluted in six parts of water. (See Cains 1992 p.154.) Once peeled off the glass the coated tissue is ready for use, either as a heat-activated or solvent-activated repair material.

Use: Rhoplex AC-234 has been successfully used, in dilutions with water and/ or organic solvent, for media consolidation on both paper and ivory supports. (See Consolidation, Fixing, and Facing: Rhoplex AC-234.) However, this particular adhesive has not been used for this purpose in the conservation of parchment artifacts. Heat-set tissue, made according to either the library of Congress formula or the Trinity College Library formula (see above), has been used both directly and indirectly in the repair of parchment artifacts. More recently, transparent membrane has been coated with the two acrylic resin dispersions, Plextol M630 and Plextol B500, for use in parchment repair. (See Adhesive-Coated Tissues and Membrane.)

Caveats: The aging properties of acrylic resin dispersions can vary widely according to how they are manufactured (especially in terms of the additives they might contain) and also how they have been applied to an artifact. In theory, all acrylics are stable to light, resistant to heat and oxidation, and have little tendency to yellow over time. (See Adhesives: Acrylic Resin Dispersions: Aging Characteristics.) Recent research at the Canadian Conservation Institute, which used natural instead of artificial aging for testing a wide variety of polyvinyl acetate and acrylic adhesives, found that the acrylic resin dispersions performed very well. However, among the acylic resins that were tested Rhoplex AC-73 was found to become very brittle and, along with Rhoplex AC-234, its pH fell within the acidic range (i.e. below pH 5) after aging (Down, et al. 1992).

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Solvents

Deionized Water

Ethanol

1:1 Deionized Water and Ethanol

Acetone

Gillis 2012 Gonzales et al. 2012 Pataki 2009

Repair Materials

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Parchment

Types of Skin

Full thickness skins: Of the three most common types of parchment that are presently used for repair work - calf, goat and sheep - the first two are only available as full thickness skins with an intact grain layer. (Although the process of splitting seems to have been done on a variety of animal skins during ancient times, and perhaps also during the medieval period, knowledge of the technique was gradually lost over time and is no longer practised.) Modern calf and goat parchment may, however, be reduced to a variety of thicknesses by scraping and/or sanding from the flesh side. It is also possible to have the grain side thinned down to some degree, if the hair follicle pattern is too pronounced or if a soft nap is desired on that side. Depending on the parchment maker, one can often special order a batch of skins for a particular job that are made from a certain type of animal (usually calf or goat) and that have a specific thickness and surface preparation. This service is currently available from William Cowley Parchment Works in England, as well as some of the other modern firms that provide the type of skins that are most commonly used in conservation.

Split Skins: Although some manufacturers sell full thickness sheepskins (i.e. Gentilli in Rome), most modern parchment made from sheepskin is only available as a split skin. (The grain splits are usually tanned and made into a very thin type of leather called “skiver”.) Although it is usually the inner flesh split of sheepskin that is made into parchment, grain splits can also be obtained from some manufacturers including William Cowley Parchment Works in England.

Parchment Shavings: Shavings that come off of new skins, as they are scraped down by the parchment maker on the frame, are used by some conservators when very thin pieces of parchment are needed for repair. (Lee 1992, p.48.)

Preparation

Thinning: If a particular thickness of parchment is needed for repair it can be thinned by the conservator using a technique described by Cains (1982/83, pp.17–18). A small piece of the new parchment is taped to a light box with the flesh side up. With illumination from below, the skin is gradually thinned using a sharpened spoke shave blade. The hair side, which does not respond very well to scraping, can be reduced to some degree by sanding or pouncing. In most instances, however, it is preferable to keep the grain layer intact since it the strongest and most compact part of the skin. Sometimes one can mechanically thin a piece of sheep or goatskin parchment by making a cut at the edge and carefully peeling away a layer from the flesh side, following the fiber direction of the skin. (Margotieva and Bykova 1991) The disadvantage of this method is that it is usually difficult to control the size and thickness of the piece that is removed, because of how the collagen fibers in parchment are oriented. It also produces a weak product which is only really useful for cosmetic work. (AC)

Toning

Sheepskin parchment (flesh splits) can be obtained pre-toned from William Cowley Parchment Works in England. These skins are currently used in many large libraries and record offices in the U.K. Many conservators however, both in the U.S. and abroad, prefer to tone their repair parchment using leather dyes. Cains (1982/83, p.22) describes a toning method using powdered aniline dyes that are diluted in water (roughly 0.25g/L) to the color of tea. The new parchment is lightly sanded on the hair side, humidified and then immersed in the cool dye bath. The skin is removed after about 5–10 minutes, drained and then tensioned on a board with clips and pins. After air drying the skin is then dried under pressure, between polyester web and blotters, before it is ready for use. (Depending upon the conditions in the workshop it may take several weeks for the moisture content in a skin dyed in this manner to stabilize. AQ)

Leather dyes that are soluble in organic solvents (ethanol or isopropanol being typical diluents) can be applied by immersing the parchment in a bath or by spraying it on the surface of the skin with an air brush.

The advantage of using solvent-soluble dyes is that the skin dries very quickly, thus enabling the conservator to tone the repair piece just before it is adhered in place. In order to match the dark purple color of a mold damaged manuscript one conservator has recently used watercolors to tone his parchment fills, much in the same way that one might tone inserts in paper conservation (Maggen 1991, p.127). Although a darker, more intense color can be achieved by the use of watercolor or acrylic paints they tend to sit more on the surface of a new piece of parchment than would a leather dye, which is more effectively absorbed by the skin. Therefore fills toned with paints can be more subject to abrasion and smearing, especially if the original artifact receives a lot of handling following its restoration.

Use

If the repair parchment is left its natural color, and not toned in an aqueous dye bath prior to use, a pre-conditioning treatment is recommended. In this case the new parchment is carefully humidified and then tensioned with clips and pins in the usual manner. This process removes a certain amount of stress in the skin (introduced during the manufacturing process) and allows the repair parchment to come into equilibrium with the workshop environment and with the artifact being treated. (AC)

The edges of new parchment are usually beveled in a variety of ways prior to repair, in order to have a better bond with the original artifact. For large inserts the parchment may be used in combination with animal membrane or reconstituted collagen, which acts as a supporting bridge on to edges of the artifact. A variety of adhesives may be used to attach new parchment - the most common being parchment size or gelatin. (See Mending and Filling.)

Caveats

The quality of new parchment purchased for repair can vary greatly according to the type of animal skin from which it was made and the way in which it was processed. Parchment made from split sheepskin is often of a uniform thickness, quite white in color, with a hard and sometimes slightly shiny surface and no obvious grain pattern. Its tensile strength is relatively poor compared to full thickness skins, but this property may be advantageous in certain situations. Skins that have the grain layer intact (i.e. calf and goat) can often have a distinct follicle pattern, depending on the degree of surface preparation. The thickness and flexibility can vary considerably across the skin so that only certain areas are suitable for use in repair. These parchments are usually warmer in color and have a softer nap than split sheepskins and are generally preferred for the repair of early manuscripts that are also made from calf or goatskins.

It is often difficult to determine the exact methods of some modern parchment makers, who may rely more heavily on the use of strong chemicals and bleaching agents in order to speed up the manufacturing process and to achieve certain visual effects with their products. It is therefore important for the conservator to familiarize themselves with the source of the parchment they are using for repair and, if possible, to provide specifications for the type of product that is desired.

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Animal Membrane

Types of Membrane

Goldbeater's skin is a thin, transparent membrane with great tensile strength which was traditionally used as an interleaf for the manufacture of gold leaf. It is made from the outer membrane or caecum of cow intestine and is composed primarily of elastin. The preparation of goldbeater's skin, described in detail by Thompson (1983) and Giuffrida (1983, p.30), is a very labor-intensive and smelly process. Although some conservators find that they have more control over the quality of the final product if they prepare it themselves (Wouters, et. al. 1992, pp. 68–69), the membrane is also available ready-made from two American suppliers, Bookbinders Warehouse and Bookmakers, as well as from Henk de Groot in Rotterdam and several companies in France.

Fish skin membrane is made from the swim or air bladder of certain species of large fish such as sturgeon, hake, cod or whiting. “These organs are essentially inflatable bladders, made from a tough form of connective tissue containing a fibre network based on a type of collagen which is called ichthyocoll.” (Reed 1972, p.131) Fish skin membrane was used by the British book conservator Sandy Cockerell in the early 1960s, for the repair of a parchment manuscript with perforated text. Its use was later described in print by Anthony Cains (1982/83). Fish skin membrane is currently avilable from the American firm of Long and Long, Belleville, N.J.

Preparation

Degreasing and pumicing the surface: In order to assure a strong bond with the artifact transparent animal membrane is usually degreased by wiping the skin on both sides with a large cotton pad dipped in acetone, or by immersing the skin in a bath of solvent. Another method of degreasing involves spraying the skin with ethanol and then dusting it on either side with magnesium silicate or Fuller's Earth. The skin is left in a closed container for about two days, after which it is removed and the excess powder is brushed off the surface.(UB) A recent study has shown that while the water-vapor permeability of goldbeater's skin is not significantly altered by degreasing, about 40% of the mean tensile strength of the skin is lost during this treatment. However, the reduction of tensile strength is not considered to be a problem when compared to the obvious benefits of degreasing. (Wouters, et al. 1992, p. 69.) Some conservators also like to abrade the surface of goldbeater's skin or fish skin to a slight degree so that it will “key” better to the object. In this operation powdered pumice or pounce is rubbed into the two sides with a cotton pad and the excess is then removed with a stiff brush. (Cains 1982/83.)

Toning with leather dyes: Although not widely practised, it is possible to tone goldbeater's or fish skin using leather dyes in the same manner in which one would tone new parchment for repair work. (see above)

Attaching membrane to a temporary backing: The mounting technique developed by Anthony Cains gives the conservator more control in handling transparent membrane, which can be very reactive when aqueous adhesives are employed. Heat-set tissue is lightly tacked onto the surface of the degreased and pumiced membrane using a heated platen press, set at 60°C. (Cains 1982/83). If such a press is not available a tacking iron or domestic iron may work as substitutes. However, because of the smaller surface area of these tools, it can be more difficult to mount a large piece of membrane without getting a lot of distortion in the skin. An organic solvent, such as ethanol or acetone, may also be used to activate the adhesive on the heat-set tissue in order to attach it to the membrane. However, if the tissue is completely wet out with solvent it may stick too well to the membrane and be difficult to remove later on.

Another temporary mounting technique developed by Ulrike Berger involves the use of polyester web as the temporary support. The polyester web is coated with a dilute solution of Tylose MH 300 in water. The prepared goldbeater's skin is positioned on the adhesive-coated web and then dried in a sandwich of polyester-web and blotters under slight pressure.(UB) Other conservators have used different types of plastic film as a temporary support for transparent membrane, but these are only applied just before the membrane is set in place over the damaged area. (See Transparent Membrane Repairs.)

Use

Since transparent membrane is so thin there is no need to chamfer or bevel the edges of the skin prior to repair. Membrane is most often used for the transparent repair of small tears and weak areas in a parchment artifact. It is sometimes used in combination with new parchment, when large inserts need extra support across the join to the original artifact (see above). Goldbeater's or fish skin can also be successfully laminated with Japanese paper, using either starch paste, PVA dispersions or gelatin as the adhesive. (See Mending and Filling.)

Caveats

Goldbeater's skin and fish skin are both natural membranes and can therefore be quite variable in size, thickness and degree of transparency. Depending on the type of processing that they receive it is often possible to buy inferior skins that were not sufficiently cleaned and that still contain a lot of fat deposits on the surface. The color can also vary as well, especially with fish skin which sometimes can have a distinctly yellowish tone. It is recommended that the conservator purchase several membranes at one time, of either goldbeater's skin or fish skin, and then separate out into groups those that are more similar to each other in color and thickness. These skins can then be selected for use in situations where they would be most suitably matched to the color and weight of the parchment that is to be repaired. (AQ)

Even when degreased and pumiced natural membranes tend to have a very smooth and somewhat reflective surface which can be distracting when applied to parchment with a soft nap.(JFM) Despite their relative thinness and flexibility natural membranes can sometimes be too strong when applied to very degraded parchments. In these cases Japanese paper is often a more suitable repair material.

Reconstituted Collagen (Sausage Casing)

General Information

A variety of different types of sausage casing are made for the food industry yet not all are suitable for use in conservation. The majority of these materials are either fully synthetic polymers or reconstructed protein fibers. Both contain several types of additives including vegetable fibers which increase their tensile strength. The width, thickness, color, transparency and strength of different sausage casing products can vary considerably. In general, they are not as strong or as transparent as natural membranes such as goldbeater's skin or fish skin. Three types of Israeli-made sausage casing, of thicknesses ranging from 0.06 - 0.12 mm, were recently evaluated for use in parchment conservation. The results showed that the collagen content differed greatly between the three samples. In addition, they all contained several impurities which, although not identified in these tests, seemed to influence the observed reduction in pH of the material after boiling. (Maggen 1991 pp.122–123.)

Preparation

Since sausage casing comes as a compressed tube it is necessary to slit it open and flatten it out prior to use. Washing the casing under running water removes the glycerin which is applied as a softening agent during manufacture. The casing is briefly immersed in a saturated solution of calcium hydroxide and then rinsed in running water. This alkaline wash is said to soften the skin for more effective use during repair. The strips of sausage casing are finally pasted out flat on a sheet of terylene or plexiglas and allowed to air dry. Once dry the strips are rolled up and stored for later use. (Woods 1986, p.6) Since sausage casing is much thicker than the natural membranes, and is not as reactive to moisture as are goldbeater's skin and fish skin, there is no need to mount it on a temporary backing for the purposes of repair.

Use

The use of sausage casing for the repair of parchment documents and other artifacts was first suggested in 1970 by Dr. James Lewis of the Imperial College of Science and Technology in England. Sausage casing made by the Scottish firm, Devro Ltd., was found by Dr. Lewis and others to be the most reliable for use in conservation, compared with similar products. It was found to be more uniform in thickness and structure, and it also has a neutral pH after processing (Woods 1986). The primary advantages of using sausage casing for parchment repair are that it is much less expensive and more readily available than goldbeater's skin or fish skin, and it is also easier to prepare and apply to an original artifact. For these reasons, sausage casing has been adopted for use in most large British libraries and record offices. Whether or not its use is as widespread in other countries is uncertain.(AQ) Although most restorers in Britain tend to use wheat flour paste for all aspects of parchment repair, one conservator recommends a mixture of rice starch paste and parchment size for mending parchment with sausage casing. (Woods 1986, p.6) In either case the adhesive is applied to a piece of prepared sausage casing, which is positioned over the tear or loss and boned in place. Sometimes the casing will be used in combination with new parchment, when a large fill needs additional support across the join to the original artifact. (See Mending and Filling.)

Caveats

Although reconstituted collagen is available in very long lengths its width is limited to the diameter of the sausage products for which it is made. Depending on the country of manufacture, this can vary from about 1 to 3 inches. Sausage casing can be made from a variety of materials including collagen and these additives can adversely affect its ageing properties. (Maggen 1991.) Some products have become brittle and weak in a relatively short period of time.(LP) Sausage casing is not as thin or transparent as goldbeater's or fish skin, nor does it have the same kind of flexibility or tensile strength as the natural membranes. Its dark color also makes it more visually obtrusive. For these reasons the use of sausage casing for parchment repair is not very widespread, with the exception of large archives and libraries in the U.K.

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Japanese Paper

Types of Paper

A variety of handmade and machine made Japanese papers are currently used for the repair of parchment. They can be laminated to match the exact thickness of the original parchment. The strength and weight of Tim Barrett's Minter Tear Guard paper, made from 100% kozo fiber, has made it useful for mending tears in parchment book leaves as well as for closing splits and breaks in parchment bindings.(JFM)

Preparation

Japanese paper can be toned prior to use with watercolors or acrylic paints. However, since the color of a pre-toned paper can often appear darker once it is applied, some conservators prefer to tone the mend after it has been adhered and dried under pressure. Relatively dry paints, pastel or chalk, lightly applied with a stippling brush, can be used to tone the repair once it is in place.

In order to make it look more like parchment the surface texture of Japanese paper can be altered in several ways. A thick wheat starch paste can be brushed on the surface of the paper, which is then dried with a tacking iron. For greater surface sheen burnish the paper through polyester web or polyester film using a bone folder. The shininess can be enhanced even further by coating the paper with gelatin and then burnishing. The flexibility of an insert can be adjusted by laminating several thinner papers together and by boarding a stiff paper or laminate.(LP)

Use

Handmade Japanese paper is currently used at Columbia University for the repair of vellum bindings and small sheets of parchment.(FB) Japanese paper can be useful for areas where a skin infill may cause too much resistance. The tissue will deform more easily, thus avoiding cockling or release of the mend.(JM) Japanese paper is often employed for multiple spine fold repairs of manuscripts when the use of new parchment would be either too time consuming or expensive.(NP) In these situations the suppleness of Japanese paper is advantageous in that it does not create a breaking edge along the spine fold. (The suppleness can vary, however, depending on the type of adhesive that is used and the weight of individual papers within a laminate.) (NS)

SC6000, an acrylic polymer and wax emulsion described by Haines (1987), has been recently used by some conservators to make a Japanese paper mend more similar in appearance to a smooth parchment. After the mend is in place, the emulsion is lightly rubbed into the paper and then burnished with a bone folder.(TW) At the Folger Library Japanese paper mends are adhered with a PVA dispersion (JADE 403) and then coated several times with a solution of Klucel-G in ethanol. Burnishing with a Teflon folder helps to make the mend more invisible.(JFM) (See also Japanese Paper Repairs.)

Western Paper

Types of Paper

Handmade western paper has been used in the past for the repair of parchment documents and manuscripts. It was used occasionally by the British book conservator Sandy Cockerell for the repair of edge tears in parchment manuscripts. He generally preferred Whatman Bank which was split in half (using traditional paper splitting techniques) in order to achieve a thinner paper.(AC) Machine-made papers were occasionally used in the 19th and 20th centuries for the repair of manuscripts and parchment documents.

Preparation

Handmade or machine made paper can be toned with watercolor or acrylic paints, although it was not commonly done by those who used the material in the past.

Adhesive-coated Tissue or Membrane

Lens Tissue Coated with Acrylic Resin Dispersions

Heat-set tissue, made according to either the Library of Congress formula or the Trinity College Library formula (see Synthetic Polymers), has been applied to transparent membrane as a temporary facing, in order to facilitate its use in the repair of parchment (Cains 1982/83, p.17). The same coated tissue has also been adhered with solvent directly to the artifact, as a means of supporting tears and perforated areas during humidification and flattening operations and for keeping fragments in alignment during conventional repair with gelatin and transparent membrane (Cains 1992).

Japanese Tissue Coated with Cellulose Ethers

A lightweight Tenjugo tissue coated with solutions of Klucel-J in ethanol or ethanol/acetone has recently been used at the Walters Art Gallery for the repair of a mold-damaged manuscript. The dry tissue is placed adhesive side down over the damaged area, ethanol or acetone is applied with a brush or a swab through the tissue, and the mend is gently pressed in place.(AQ)

Frank Mowery makes an extremely thin and transparent repair tissue from kozo fiber which is formed on a leaf caster. (The product, called Gossamer Tissue, is commercially available from Bookmakers international.) A thin solution of Klucel-G in water is applied to the tissue by brush or spray, or by using a roller through a piece of screening material. It is especially useful for overlaying damaged areas of text or illumination in documents and manuscripts on both paper and parchment supports. The adhesive-coated tissue is positioned over the damaged area and the adhesive is activated by moistening with ethanol or acetone.(JFM)

Japanese Tissue Coated with Isinglass

A medium weight Japanese tissue, coated on one side with a solution of isinglass, is currently made by Tatyana Petukova, a paper conservator at Cornell University (Petukhova and Bonadies 1993). (Although not readily available at the present time the product may be marketed commercially in the near future.) It has been used at the Pierpont Morgan Library for the repair of parchment. Once the repair tissue is positioned the adhesive is activated with moisture, introduced through Gore-Tex. The application of the mend can thus be very gentle and controlled.(DE)

Synthetic resins on transparent animal membrane

Transparent membrane coated with methacrylates

A solution of Acryloid B-48N in toluene has been applied to goldbeater's skin and used for the repair of an ethnographic object made from the bodies of small birds. (Kaminitz and Levison 1988.)

Transparent membrane coated with acrylic resin dispersions

The two acrylic resin dispersions, Plextol M630 and B500 (prepared in the same manner as for Trinity College Library heat-set tissue - see Synthetic Polymers) have been recently applied to transparent membrane (fish skin) and used for the permanent repair of cracked and perforated parchment manuscripts that have been damaged by acidic media. (Cains 1992, p.155.)

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Pulp Filling/Leaf Casting Materials

Purified Hide Powder

This technique was recently developed in Belgium (Royal Institute for Cultural Heritage, Brussels) for the repair of a severely mold-damaged illuminated manuscript on parchment. (Wouters, et. al. 1993.) The method uses a hide powder which is prepared from calf hides that are limed, delimed, dehydrated with acetone and then milled. (This powder, which is made for other commercial uses, is obtained from the Leather Trade House, Northampton, England.) An aqueous suspension of hide powder is prepared in 0.03% Tylose MH300. Mild pretreatment with formaldehyde and additional calcium carbonate may be used to tune the opacity of the final preparation. In order to assure that no residual formaldehyde remains in the final pulp mixture, thorough rinsing is carried out until a negative test with the indicator fuchsin is obtained. (The use of this pulp mixture for repair work is described in Pulp Fills.)

Hide Powder and Eukanol Glanz N

This pulp filling technique was developed by the Danish paper conservator Per Laursen. (Laursen 1985.) The so-called “parchment” powder is not made from new parchment but from goat or calf skins, which are obtained from a commercial tannery in a raw state, cleaned of their hair and flesh. The wet skins are delimed in a large vat, dehydrated with alcohol and then hung up to dry. The skins are cut into small pieces and ground into a powder using a grinding machine. The powder is used in this pure state, without the addition of any other materials, for the filling of losses in parchment artifacts. (It can be obtained ready-made from Mr. Per M. Laursen, Baunebjergvej 113, DK-3050 Humlebaek, Denmark.) Since the powder is applied with an atomizer in a dry state an adhesive is then added in a second step, in order to bind the fill together and make it adhere to the original. The particular product chosen by Laursen, Eukanol Glanz N 103 543, is made by Bayer in Germany and consists of a synthetic casein which contains aluminum. (It is normally used in the leather industry as a surface finish for tanned and dyed skins.) For pulp filling the adhesive is diluted with ethanol to make solutions varying from 10% to 50%, depending on the particular situation. It is applied to the pulp fill using either a brush or a spray gun, while the object is on the suction table. The suction draws the adhesive through the layer of powder and binds the fibers together. In the case of very large fills it may be necessary to apply a layer of goldbeater's skin to either side for additional support. (See Pulp Fills.)

Parchment Powder and Ftorlon

This technique is used in Russia primarily for the repair of mold-damaged manuscripts. New parchment is either shaved down or pulverized in order to make a powder, which is then sieved until the desired particle size is achieved. The parchment powder is mixed with a 5% solution of Ftorlon 26 in 1:1:1 ethylacetate/butyl-acetate/acetone and then used to fill losses in parchment artifacts. (See Adhesives and Consolidants and Pulp Fills.)

Hide Powder and Paper Pulp

This technique of pulp filling was developed at the National Library in Budapest, Hungary and used for the repair of a large collection of mold-damaged manuscripts dating from the 15th century. (Beothy-Kozocsa, et. al, 1987 and 1990.) The pulp contains a wide variety of materials including parchment powder, five different types of paper fiber, two adhesives, water, ethanol, isopropanol and a fungicide. The so-called “parchment powder” is obtained from a type of limed, yet untanned hide called “Picker” which is used in the textile industry. The hide is cut into strips, pulverized on a grinding wheel and then seived. Before adding it to the pulp the “parchment powder” is swollen in water for 24 hours. Sulfide or sulfated pine cellulose, obtained in an aqueous suspension from a commercial papermaking company, is ground and dried, and then mixed in an alcohol solution with the addition of a fungicide. The ground fibers of four different types of Japanese paper are then added to the pine cellulose to make a final pulp mixture containing 30 g of dry fiber in 2000 ml distilled water. Parchment glue is prepared according to Wächter's recipe (see Adhesives and Consolidants: Parchment Size) which includes wine vinegar and alcohol as additives. The second adhesive consists of a 7% solution of hydroxyethylmethyl cellulose. Once prepared all of these materials are blended together and the mixture is allowed to sit for several days until it is no longer foamy. Regular agitation of the pulp avoids settling of its contents. Although coloring agents such as pigments or dyes may be added to the pulp at this point, the conservators in Budapest usually prefer to alter the color of the pulp by the selection of Japanese papers that go into the mixture.(AQ) (This method is further described in Pulp Fills.)

Parchment Powder and Glacial Acetic Acid A European technique whereby acetic acid is added to a small loss filled with parchment powder. The acid gelatinizes the powder and makes it adhere to the original. The disadvantage of the technique is that acetic acid can cause the parchment around the perimeter of the loss to soften.(PY)

Lining and Lamination Materials

The following materials and methods are no longer recommended for use in conservation for the following reasons. They have been found to severely limit the ability of parchment to respond to changes in the surrounding environment, thus leading to damage in the original artifact. The reversibility of the laminating materials and adhesives is also highly questionable.

Polished Cotton or Linen

Cotton or linen fabric was frequently used in the past in many libraries and archives for lining paper as well as parchment documents, maps and other archival materials. Flour or starch paste was typically used to attach the lining to the artifact. In the U.K. cotton or linen fabric was primarily used during the two world wars for the lining of parchment documents. (Prior to that time new parchment was more typically used as a lining material for parchment documents.)(FB)

Silk Crepeline

A very fine weave silk fabric, often called crepeline, was sometimes used in the past for the lamination of parchment manuscripts and documents. Flour or starch paste was commonly used to attach the silk to the artifact. Up until the introduction of heat-activated laminating films in the early 1960's, silking was widely practiced in large libraries and archives and in commercial binderies, both in the U.S. and abroad. Many manuscripts were repaired with silk in the 1950's by a commercial binder in Cambridge, England.(NP)

Mipofolie

Mipofolie is a plastic laminating film that was made in the 1950's by the German firm Alfred Schwarz Gmbh & Co. Analysis of the material has identified it as a vinylchloride polymer, externally plasticized with 30% (w/w) bis(2-ethylhexyl) phtalate (otherwise known as dioctylphtalate). (See Wouters, et. al. 1990.) Mipofolie was used for the lamination of deteriorated parchment manuscripts and documents in Europe during the 1950's and perhaps earlier. Although it was commonly applied with heat, some authors have suggested that an adhesive such as poly(vinyl)acetate was occasionally used to attach the plastic film at room temperature and using only moderate pressure. (See Wouters, et. al. 1990, p.497 and Wächter 1987.)

Dry Mount Tissue

Dry mount tissue, and other types of heat-set tissue, are still occasionally used by modern commercial framers for the mounting of parchment documents - often with disastrous consequences. The tissue is usually attached to the artifact with the use of a dry mount press, with the temperature of the press set to the activation temperature of the adhesive.

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History of This Page

This page was created in April 2022 when the Parchment page was updated.