BPG Western Papers

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Rag Papers

Rag papers were originally made from flax/linen rags and cuttings. From the late eighteenth century, cotton fibers were used or mixed with the flax fibers, also in the form of rags and processed cuttings. Rags were used because the value of the raw fibers for textiles put them beyond the means of papermakers. Raw fibers or new cloth made a paper that was too rigid and did not beat or fibrillate as well. Most rag papers today are made by adding cotton linters and using some fibers derived from fabric scraps. There are also “rag” cotton content papers which are as low as 25% cotton with mixtures of other fibers.

Only a few handmade paper mills use rag cuttings because there is no longer any collection of rags on a large-scale basis and the difficulty in obtaining pure cotton or linen rags. These mills use 100% natural-fiber fabric scraps obtained from textile mills and clothing factories and, more often, cotton linters. The increased brightness of paper produced during the latter years of the eighteenth century was a result, in part, of the increased use of “brighter” cotton fibers (Robison 1977, 49).

Inherent Problems

The increasing mechanization of paper production had a compromising effect on paper quality. For example, the Hollander beater, introduced in the 1600s, chopped the fibers into shorter lengths. The early stampers, by contrast, rubbed, frayed, and spread (fibrillated) the long fibers. Paper made from fibers beaten in the Hollander is not considered to be as strong as that made from rags beaten in stampers; it is shorter fibered, less fibrillated and therefore may be weaker and less durable. The Dutch added more sizing which compensated for short fibers and gave strength.

Handmade rag paper originally had a deckled edge with irregular folded edge flaps and edge cockles; in many cases the deckles have been trimmed. Early rag papers often show marks or fine, striated creases on the back from being draped over a rope to dry. These creases (called backmarks) are of historic interest. If the creases are removed during treatment, gaps may occur in design areas. Early rag papers may be a wide variety of off-white colors. This range of possible original colors should be considered in planning conservation treatments.

Treatment Observations

Linen rag papers tend to retain papermaking and printing characteristics even after water treatments if carefully dried. Cotton rag papers do not retain the impression of printing after washing as well as linen papers. They do, however, retain impressions much better than papers made from cotton linters or wood pulp. It may be difficult to remove distortions from rag papers.(AD) As each sheet of handmade paper differs one from another, on should respect the integrity of the sheet and its subsequent use. Care should be taken to preserve the deckled edge and back marks.

Mechanical Wood Pulp Papers

(Ground wood pulp, thermo-mechanical pulp, refined-mechanical pulp; for more details on these individual processes see, for example, Hills 1988, 146.)

The structure of the debarked log (usually softwood) is broken down by applying intense mechanical action with grinders or refiners in the presence of water. The attraction of this method for papermaking mills is the high yield, and for consumers the inexpensive paper produced. Physically and chemically this paper is inferior; its fibers are short (average length is 3–4 mm), inflexible, and the finished sheet lacks cohesion. In addition, most of the lignin as well as the tannins, metallic salts, etc., remain in the paper. Wood pulp papers can be bleached to various degrees of whiteness, but diminish in brightness and discolor with age. The product is generally opaque, has good bulk, and good printability; it is used for newsprint, magazine and other printing grades.

Inherent Problems

“The presence of lignin is indicative of a chemically unstable paper. Lignin promotes brightness reversion (yellowing) and oxidation of the cellulose, contributes to total acidity and readily deteriorates photochemically.... Residual lignin in wood pulp is chemically altered from its native state. Often it is less stable, and breakdown creates byproducts that can accelerate the degradation of the cellulosic components of paper” (Young and Burgess 1989, 14–15; see also Lyall 1982, 72). This increase in the rate of the degradation of cellulose accelerates embrittlemen. In the past, chemical pulp or other stronger fibered pulp has been added to newsprint to strengthen it so the web could be carried over the papermaking machine successfully. Recent developments have given mechanical pulp greater suppleness and bonding capacity using little, if any, reinforcing chemical pulp. Ground wood papers deteriorate rapidly, even when stored under the commonly accepted conditions of 68°F (20°C) at 50% RH. Mechanical ground wood pulp paper darkens (yellows) rapidly if exposed to light and atmospheric pollution.

Treatment Observations

The preservation of ground wood paper is a difficult problem. Until the mechanism of the degradative processes is understood it will be difficult to treat valuable items with confidence (Lyall 1982, 84). The long-term preservation of these papers may not be possible. Washing to remove acidity and degradation products, deacidification, proper housing, and limited exposure to light improve chemical stability of ground wood papers. In some collections, such as archival materials, changes in paper tone and texture which result from washing, deacidification and alkalization, are considered acceptable modifications since chemical stability is enhanced.

Bleaching (oxidative, reductive) usually lightens the color of darkened ground wood paper initially; however, darkening may occur later. (See 19. Bleaching 1988, for details.) It may also unduly brighten a ground wood paper that was never bright white.(KN) Sun bleaching may not be appropriate for lignin-containing papers; may cause darkening or random spots.(NA)

Alkalization is a logical treatment for acidic ground wood papers, but it usually darkens, yellows, or grays the paper. The choice of alkalization treatment will have an effect on the paper color that results immediately after treatment. Some research (e.g., Lyall 1982, 83) suggests that alkalized paper will show less cumulative darkening after aging than non-alkalized paper so that both will end up about the same color. Choosing not to alkalize means that there will be no neutralizing of the inherent acidity. Washing before alkalizing will lighten the paper a great deal. Not only does this counteract the darkening associated with the alkalizing, but it also addresses the acidity.(CS) Some conservators feel that the alkaline buffer may get used up quickly in an acidic, reactive ground wood paper and that the benefit of alkalization may last only a few years.

Photochemically induced yellowing of ground wood pulp paper has been shown to be caused by light of wavelengths 355 to 400 nm (Lyall 1982, 84). To minimize yellowing, exhibit with UV filters at low light levels for a restricted period of time.

Encapsulation in polyester can preserve newsprint items and manuscripts which will be handled. If alkalization of the paper support is not part of the treatment before encapsulation, some conservators feel a sheet of alkaline paper should be inserted behind the object inside the polyester film. (See Shahani and Hengemible 1986 for considerations regarding encapsulation of modern papers and insertion of alkaline paper sheet.)

Housing in buffered board provides neutralization and improves chemical stability.

Reduction of temperature and maintenance of constant relative humidity may delay deterioration.

Material on ground wood paper (e.g., newspapers, periodicals, some books) can be microfilmed as an alternative to preserving the original. Microfilming is not an acceptable solution for works of art or manuscripts on ground wood pulp paper. Although microfilming, photography, or photocopying may be done to reduce the handling of archival materials.

New technologies may provide future preservation options.

Chemi-Mechanical and Semi-Mechanical Pulp Papers

(For more details on all these processes see, for example, Hills 1988, 153.)

In chemi-mechanical pulps the chips are treated very rapidly with nearly neutral sodium sulfite liquor before refining in a modification of the mechanical refiner process (85–95% yield). In semi-chemical pulps the wood chips receive a mild chemical treatment before being defibered in refiners (60–85% yield). These pulping operations remove only part of the lignin in wood fibers. Also see Hills (1988, 208) for the use of waste or recycled paper with wood pulp.

Inherent Problems

“Little specific information is available on the chemical effects of Neutral Sulfite Semi-Chemical (NSSC) residual lignin on paper permanence, but the stability of paper made from this type of pulp has been investigated...(A) calcium carbonate buffer may improve stability....In the absence of buffering, its stability may be no better than that of thermo-mechanical wood pulp” (Young and Burgess 1989, 15).

Treatment Observations

See Mechanical Wood Pulp Papers.

Chemical Wood Pulp Papers

(Soda, sulfate/kraft, sulfite processes–for more details see Hills 1988, 149.)

Economically viable processes for chemically converting wood into pulp for papermaking were not developed until the 1850s. The earliest was the soda process developed by Burgess and Watt in England in 1851; an American patent was secured in 1854. Using chemical wood pulp, a white paper suitable for printing could be made from wood. The sulfite process was developed in 1857 by the American, Benjamin Tilghman. Commercial production of this pulp began in 1887 at Cornwall, Ontario.

The two main chemical pulping processes today are the sulfate and the sulfite methods. Today, the term “sulfate” designates all paper pulps made by a process which uses sodium sulfate as its main chemical constituent. Exceptionally strong grades of paper and board are produced from unbleached softwood sulfate pulp. Hardwood sulfate pulps are also produced (Roberts and Etherington 1982, 254). One such paper is commonly referred to as kraft paper.

Sulfite pulp is usually made from softwoods. The wood is digested with a calcium (or other) acid sulfite cooking liquor. “Sulfite pulping is superior in the amount of lignin removed, and produces papermaking fibers that are white in color and can be bleached to higher whiteness with (fewer) chemicals than required for the sulfate process” (Roberts and Etherington 1982, 254). The paper made from sulfite pulp is not as strong as that made from sulfate.

Wood chips are heated under pressure with solutions of chemicals which dissolve out the cementing lignin. Then the chips are broken down into a fibrous slurry using very little mechanical force. Fibers contain very little lignin and paper can be made with high color stability and permanence thus meeting the need for a more durable and lasting paper from wood. Bleaching normally removes the last traces of discoloring lignin so the purest pulps contain only polysaccharides. This is achieved with some reduction in the polymer length and introduction of new chemical groups (e.g., aldehydes). This does not necessarily mean that the resulting paper will be less permanent.

Inherent Problems

Since there is a wide range of chemical wood pulp papers, inherent stability can vary.

Kraft paper is observed to deteriorate rapidly in some cases, but often is seen to have surprising strength, possibly through the introduction of borax, either to the paper itself or to the adhesive used in conjunction with contemporary kraft paper tapes.

Alum-Rosin Sized Papers

Alum (K₂SO₄ · Al₂(SO₄)₃ · 24H₂O) (Roberts and Etherington 1982, 9) has been used since the seventeenth century, and possibly earlier, as a hardener for gelatin sizing; as traditionally used, alum is weakly acidic in solution. The term alum originally referred to potash alum KAl(SO₄)₃ · 12H₂O. A new process, patented in 1807 and in common use by 1870, used aluminum sulfate (also called alum or papermakers' alum), which was cheaper, combined with rosin sizing. In it, aluminum resinate was precipitated onto the paper fibers in the pulp stage, leaving a residue of sodium sulfate and free sulfuric acid that led ultimately to the sheet's deterioration, particularly since the papermaker tends to “overdose with alum” (Roberts and Etherington 1982, 9). Rosin or modified rosins are used for the internal sizing of paper; addition of aluminum sulfate is required to link the negatively charged rosin soap to the negatively charged surfaces of the paper fibers. Thus, the alum renders the rosin insoluble so that it can impart water resistance to the paper. For the papermaking industry the alum-rosin sizing system is a reliable and cost effective means of sizing.

Inherent Problems

• Deterioration of papers that are alum-sized vary greatly and is not always detectable in papers with alum added to gelatin.

• “While alum is not a particularly strong acid, in the presence of certain other substances it can assume a greater strength...Excessive alum, in the form of aluminum sulfate, may react with chlorides present to form aluminum chloride (AlCl₃), which in the presence of moisture and heat, will form hydrochloric acid (HCl)...” (Roberts and Etherington 1982, 9).

• Rosin is known to darken easily from exposure to light, elevated temperature and low relative humidity; this sizing appears to become quite brown if exposure is prolonged.

• Alum-rosin size was often applied to very thick nineteenth century Whatman papers. Recently examined samples showed low surface pH, however, inherent strength still appeared good.(SB)

Treatment Observations

• Reducing the darkening of the alum-rosin sizing is difficult. Until it is known how discoloration develops in this sizing and whether existing bleaching methods effectively prevent its recurrence, it is not known whether such treatments will provide anything other than short-term cosmetic effects (Perkinson 1986, 8).

• Washing alone may significantly improve the darkened appearance of alum-rosin sized paper. If these papers are housed properly and exhibited with UV filtration, darkening may be reduced for some time.

• Alum-Rosin sizing increases the light absorption of paper in the 330–440 nm region of the electromagnetic spectrum. Rosin-sized papers also yellow in natural light. This may be a contraindication to light bleaching.

• If resizing is thought necessary, use of synthetic products or gelatin might be considered.

• Some solvents affect sizing, cause tiding, and change absorbency of paper. This can be a problem, particularly with local treatments.(LP)

Colored Papers

Paper may be given an integral color through the choice of raw material or by mixing coloring matter into the pulp. Color may be added to the surface of the sheet during sizing or by sponging or brushing it on or by giving the sheet a colored ground or coating after manufacture.

• Colored rags: Paper made from colored rags often has a mottled “color texture” since individual fibers or clumps of fibers from different rags are apparent. Old master drawings were frequently executed on blue paper because indigo was the only dye used for coloring rags, which would survive the fermentation, beating, etc. steps of the papermaking process (Long 1979, 68). Evidence for paper made from rags in a color other than blue, grey or brown is rare before 1796; rose colored papers are considered very rare.

• Vat-dyed: Dyes or pigments are added at the beater, the size press, or the calender stacks; the latter two are surface coloring procedures. Greater color penetration is achieved at the size press, since the paper web is looser, than at the calender stacks. By the eighteenth century blue colorants were known to have been added to the vat (Cornely 1956, 44–60 referenced by Krill 1987, 61).

• “Corrected white paper, a modern term, was paper which had a slight tint of blue, or occasionally red, added to it” (Krill 1987, 90). The whitener was added to correct the otherwise yellowish cast of the sheet. It became very popular in the eighteenth century (Krill 1987, 92) and continued in use (for example, charcoal drawing supports of Odilon Redon). Corrective whiteners include blue fibers and colorants such as indigo, smalt and Prussian blue. An advantage of indigo over smalt is that it spreads more evenly through the stock. The natural creamy tint of early modern rag paper was obtained by adding ultramarine blue. To obtain a creamier white, cochineal pink was added (Clapperton 1929, 122). The addition of red fibers has also been observed. Cheaper aniline dyes were also used but they may not be lightfast.

• Optically brightened: A colorless dye absorbs light in the UV region of the spectrum and re-emits it as fluorescence in the visible region. Most optical brighteners are stilbene derivatives. They are often added in papermaking to “brighten” paper: their blue fluorescence complements the yellow cast of natural fibers and the eye perceives whiteness. Pigments, fillers, etc. are often added to optically brightened papers to produce further modifications of the yellow tint. Toners or brighteners, fillers, etc. are very common in poster papers (19th century to modern).(SRA)

• Some pigments and dyes used to color paper include smalt (pieces of blue glass), ultramarine blue, logwood (produces black, blue, and gray), ochre and other earth pigments, cochineal, indigo, Prussian blue, turnsol, woad, etc. (see Labarre 1937 and Krill 1987 for further listings).

Inherent Problems

• One of the most difficult tasks for a paper conservator is to determine the original color of the paper. Important elements to consider include aesthetic considerations, close examination of the paper, comparison with similar works, interaction of the media and paper, analysis of paper fibers, and paper colorants. (For a specific application involving these considerations see Perkinson 1986, 1.)

• Unstable pigments and dyes may fade in light Exposure to UV light over an extended period of time may change the structure of an optical brightener so that it no longer functions as a UV absorber and cause the paper to appear yellow.

Treatment Observations

• Consequences of treatment procedures (washing, alkalization, stain removal, etc.) must be carefully considered. Unstable pigments (usually organic) and dyes may change color. For example, Prussian blue, a known colorant of gray-blue and gray-green papers from the 1770s, can be decolorized by alkali solutions.

• Optical brighteners may be unstable to some wash solutions and bleaches; organic solvents used in tape removal, etc., may remove or dissolve optical brighteners.(KN) Optical brighteners can also change solubility over time.(KDB)

To verify the presence of an optical brightener examine under an ultraviolet lamp. To identify the fluorescing species use comparison sheets of known brightness, analyses, and spot tests.

• Water and solvents may also remove color additives such as a contemporary paper dye. Tidelines are easily formed in colored papers with local solvent treatments.

• Surface color can be adversely affected by overly vigorous surface cleaning due to abrasion or changes in optical qualities which alter visual perception.

Calendered Papers

A paper (or cloth) that has been given a smooth surface by passing it one or more times through a calender. These are “horizontal cast iron rolls with hardened, chilled surfaces resting one on another in a vertical bank at the dry end of the papermaking machine” (Roberts and Etherington 1982, 44). Types of finish include: a) antique: a paper that receives a minimum of calendering; b) machine and English: a paper that receives increasingly more calendering; and c) super-calendered: a highly glazed paper (Roberts and Etherington 1982, 44).

Inherent Problems

Loss of calendered surface. Surface abrasion or burnishing will leave visible marks on a calendered surface.

Treatment Observations

• Aqueous treatment may cause alteration of the compacted, often shiny paper surface through swelling of the paper fibers with moisture contact. Characteristics of the calendered surface may be difficult or impossible to reintroduce.(NA) The high pressure and hard surfaces used in the original papermaking process are needed to recreate the characteristic surfaces.

• If media permit, surface character can be reestablished with a variety of techniques: drying face down on glass with pressure from above, spraying with very dilute gelatin solution and drying face-down on silicon release or polyester film, or burnishing (directly on object or with an interface to increase/decrease gloss).(CS) Where media allows, flattening in a press between rag board may be more successful in restoring surface than pressing with blotters under weight.(LP) It may be possible to use a barrier sheet such as silicone release or glassine.

• To reduce surface dirt, use grated white vinyl eraser, lightly rubbed. It may not be possible to remove all surface grime.(AS)

Loaded Papers

The addition of mineral material to the paper stock before sheet formation is called filling or loading. Fillers are finely divided, relatively insoluble, white powders which are added into a papermaking stock either directly or by chemical processes (Roberts and Etherington 1982, 161). “Loading was first used in the 19th century, apparently surreptitiously, to save pulp and reduce the cost to the papermaker” (Roberts and Etherington 1982, 161). Such papers were considered inferior. Today fillers are considered to have many benefits and are required to achieve certain paper qualities. For example, in printing papers fillers increase opacity and brightness and improve printability (smoothness, ink absorption, and penetration) (Casey 1981, 1520). Softness and dimensional stability are also improved. Fillers are used especially where optical properties and printability are more important than strength. Typical fillers used today include clay and calcium carbonate. The fillers most widely used in magazine, book, and other printing papers are talc, titanium dioxide (its high opacifying effect reduces show-through after printing), zinc sulfide, calcium sulfate (gypsum), diatomaceous silica, and “blanc-fixe.” These are practical as fillers because of their whiteness, high refractive index, small particle size, chemical inertness, cheapness, etc. (Casey 1981, 1516).

Gypsum (calcium sulfate) was used for the first time as a “loading” material in 1823 according to Hunter (1978, 540) although Cohn (1982, 10) cites a 1797 report that the calcium sulfate compounds, alabaster and gypsum, were used to load engraving papers. Imitation art paper is a printing paper containing a high percentage of China clay, kaolin, etc. in the paper furnish (Roberts and Etherington 1982, 136). (For early use of China clay see Hunter 1978, 490. For fillers in Japanese papers see Lining: Materials and Equipment).

Inherent Problems

• Rapid absorption of liquids; increased penetration.

• Decrease in strength. The strength of paper is mainly a result of fiber-fiber interactions; pigment particles between the fibers will interfere with fiber interactions (Casey 1981, 1528). Thus, the addition of fillers weakens the sheet structure. In sheets of the same basis weight, the sheet containing filler will contain less fiber than the unfilled sheet, and will be weaker.

• Alkaline loading materials, such as calcium carbonates, may act as a buffer. This explains the relative good condition of loaded papers made from poor quality fibers.(LP)

• Deep creases, folds, and dents to these papers often result in a distinctly different color along the line of damage. (CS)

Treatment Observations

• Water stains loaded papers very easily (e.g., gray East Asian clay-loaded papers favored by Matisse for lithographs).(KN)

• Lack of internal and surface strength may cause problems with hinges shearing off and mends and infills may be difficult to remove. Moisture must be kept to a minimum in the above treatments to avoid tidelines and staining.(TF)

• Loading of calcium sulfate may be lost in repeated cycles (five) of float washing/drying (Cohn 1982; Daniels 1986, 71–72). Loadings in papers used in modern posters can be lost in water washing.(KDB)

• See also Japanese Papers

Artists' Coated (Prepared) Papers

• Metalpoint papers: White papers were traditionally coated with a liquid ground, usually white lead or powdered bone or shell, sometimes mixed with colored pigment. The binder was usually gum arabic or animal glue. The dried ground was burnished. More recent grounds have included barium sulfate, zinc oxide, titanium oxide and other modern white pigments.

• Dry-tinted papers: Dry pigment or pastel is rubbed into surface.

• Wet-tinted papers: Paper is dampened and sometimes stretched; it is then tinted with a thin glaze of watercolor, drawing ink or other aqueous colorant. M. W. Turner, for example, is known to have prepared his own papers. “One such paper is known...to have been stained with ‘tobacco juice and Indian ink” (Richmond 1990, 4).

Inherent Problems

• Artists' coated papers may exhibit abrasion or burnishing of surface, flaking of ground (caused by drying out of binder and aggravated by an excessively dry environment), inability of coating to withstand the dimensional response of paper to fluctuating relative humidity, creasing and folding of paper.

• Stains form easily in the absorbent ground layer which limits use of aqueous treatments to reduce stains or discoloration. (NA)

• If the coating is heavy and applied to only one side of the sheet, humidity fluctuations over time may result in draws, undulations and bulges that are impossible to remove. Heavy inks on top of the coating magnify the problems (e.g., silkscreens by Andy Warhol and Josef Albers).(CS)

Treatment Observations

(See Coated Papers).

Coated Papers

Coated papers are paper (or board) which has had its surface modified by the application of clay or other pigment and adhesive materials, etc., to improve the finish for its intended use (Roberts and Etherington 1982, 57). After the second half of the nineteenth century, a sustained technical effort led to the development of mechanical methods for coating paper on a commercial scale, either on the actual papermaking machine or on a separate machine. Coating of papers has been used widely during the twentieth century to give a smooth surface for printing, especially for the photomechanical printing of illustrations (e.g., the reproduction of fine half-tone blocks). One or both sides of the paper substrate may be coated to give a more uniform/more receptive surface on which to draw or print than is obtained with uncoated fibers. Coatings control ink absorption and ensure even transfer of printing ink. They enhance graphic reproduction, especially with multiple colors, and increase opacity and gloss of paper. A coated sheet may be calendered to impart a higher gloss. Coatings can also give the paper a different color.

• Pigment coating: A pigment-coated paper consists of a base paper covered by a layer of pigment particles (most common include clays – usually kaolin, a refined clay – titanium dioxide, calcium carbonate), and zinc oxide (for direct electrostatic copies [KN]); an adhesive binder (animal glues, pre-1895; casein, late nineteenth century; starch, early twentieth century; soy protein; synthetics, late 1940s) which holds the pigment particles together and to the surface of the paper; and some auxiliary agents (defoamers, lubricants, wax emulsions, preservatives, flow modifiers, insolubilizers, etc.) (see Casey 1983, 2013–2189).

• Functional coating: These coatings are designed for purposes other than printing enhancement, to produce surfaces with functional properties (barrier, etc.).

Inherent Problems

• Some have little strength. Can be very stiff and/or brittle.

• Zinc oxide and titanium dioxide are known photosensitizers of cellulose.

• Coated papers are generally very sensitive to and easily damaged by moisture or humid conditions.

• The surface of a coated paper is easily damaged or stripped. Scratches and abrasions scar and dull or burnish the finish.

• Heavily coated papers or embrittled coatings can crack or flake and the coating can pull away.

• The surface can absorb extraneous material like resins or oils from adhesives. This causes embedded stains which are difficult to remove (Baker, van der Reyden, Ravenal 1989, 1).

• Inks or paints applied to a coated surface may not bond well, resulting in cleavage. For example, Andy Warhol's silkscreens.(CS)

Treatment Observations

• Options for the conservation treatment of coated papers are limited. The use of dry cleaning agents or solvents to remove dirt and stains can lead to cracking and flaking of the ground or to changes in surface appearance (color, refractive index or reflection change) (Baker, van der Reyden, Ravenal 1989, 1).

• Coated papers that have become wet will fuse together as they dry. If adequate steps are not taken to separate and treat the material when it is still wet, permanent damage can result Freeze-drying has proven especially useful for some, but not all, types of coated papers (Parker, 1989, 4–6,8).

• Solvent treatment can cause ring stains.

• Washing can darken clay coatings. Also, characteristic surface gloss is altered by wetting; this is difficult to recreate through conservation treatments. (NA)

Western Tissue Papers

Western tissue papers are very lightweight paper made from any type of pulp and may be glazed or unglazed. Some tissues are relatively transparent (Roberts and Etherington 1982, 265).

• Glassine tissue: A translucent paper formerly produced by heavy beating in the pulp stage, followed by acid surface treatment. Currently neutral glassine is made translucent with glycol. Glassine is often used with works on paper as a “heavier-weight” interleaving or “slip-sheet” tissue when translucency and great smoothness is important. (See also Matting and Framing: Materials and Equipment: Cover Tissues)

• Soft tissue: The soft tissue industry developed in the United States during World War I. Soft tissue is absorbent and strong. It is often made of a combination of high-grade waste and wood pulp.

Inherent Problems

Glassine tissue: Acid-process glassine is, of course, inherently acidic.

Treatment Observations

• Very sensitive to water, expands greatly when wet and distorts readily.

• Neutral glassine may be suitable for temporary interleaving purposes though sharp edges may be problematic near fragile media on paper supports and it may become more acidic in time. It is very reactive to moisture, distorting severely and is dimensionally unstable with environmental cycling. Nevertheless, many collections prefer to use glassine because it is “see through.”(NA)

Tracing Papers

A thin paper with a hard, smooth surface characterized by excellent optical transmission properties. “Important properties include proper receptivity to drawing ink and transparency, so that prints from the tracings can be made” (Roberts and Etherington 1982, 267). Tracing papers before the late eighteenth century rarely survive due to their fragility.

• Prepared tracing paper: Linen—flax, hemp, or linen rag—(nineteenth century) and cotton (twentieth century) pulp papers are impregnated in a separate operation with gums, oil and/or resin to transparentize (Mills 1986, D62–3). Mills identified drying and non-drying oils, pine resin, etc. in GLC-MS analysis of some nineteenth century English tracings.

• Parchment paper (vegetable parchment), Pergamyn, Papyrine, etc: The already formed but unsized paper sheet is subjected to a brief sulfuric acid bath. This “attacks and dissolves the cellulose and changes its fibrous form... (so that it) is altered in character to resemble parchment” (Yates 1984, 21). Then the sheet is washed in water, given a dilute ammonia bath to neutralize the acid and, sometimes, a coating or bath of glycerine or glucose. “On drying the paper shrinks considerably but it is greaseproof and much stronger” (Yates 1984, 21). Early parchment papers were made from rag papers; modern “vegetable parchments” are made from sulfite pulp paper.

• Imitation parchment (vellum): Chemical wood pulp paper given a prolonged beating or sulfuric acid treatment to render it grease resistant and waterproof and partially transparent. This is “a type of relatively strong paper first produced by W.E. Gaine in 1857...(it) is called imitation parchment in order to distinguish it from parchment paper made in imitation of true (animal) parchment” (Roberts and Etherington 1982, 136).

• Natural tracing paper: “Natural tracing papers are manufactured from selected wood pulps to give an optimum balance of translucency and strength. The mechanical treatment of the fiber, or refining, is designed to maintain fiber length and change the structure of the fiber to increase its surface area. During the formation of the sheet of paper, it is this feature which contributes most to the construction of a dense sheet of cellulose. Further compression and compaction of the sheet produces a paper virtually void of interstices, thus free of internal light-scattering interfaces. Unlike prepared papers, natural tracing papers are substantially free of papermaking chemicals. The paper is made at pH conditions close to neutral and the temperature at which the paper formed is high enough to kill most of the microbiological organisms that could cause paper decay. It therefore follows that modern natural tracing papers do have good aging characteristics. Even the size which is applied to give a surface receptive to drafting inks is selected to minimize acid hydrolysis” (Rundle 1986, D64–65). Natural tracing paper of circa 1825 has been observed at the National Archives and Records Administration.(KN) As developed in U.K. in 1939, the process included the addition of starch, but by 1950 starch was no longer required to produce translucency. Scanning electron micrographs of modern natural tracing paper show general fiber damage and fibrillation, but no impregnating agent (Priest 1987, 76).

• Onion skin: “...Thin, highly glazed translucent paper” (Yates 1984, 21).

• Waxed paper: “Paper passed through a bath of melted wax” (Yates 1984, 21).

Inherent Problems

• Tracing papers in general react very dramatically to moisture changes; they expand, cockle and wrinkle easily. Oil/resin prepared tracing papers are less reactive, however, than natural tracing papers which have a greater capacity to expand with moisture. Cockling of the support around pigment wash areas may be an inherent characteristic of some works on tracing papers.

• With aging, prepared tracing papers may become extremely brittle and discolored because of the presence of impregnates, especially when stored in a poorly regulated, acidic environment. (SRA)

• Translucency makes the addition of unobtrusive hinges, mends, fills and linings problematic.

• Adhesion of starch pastes are problematic with some impregnated papers.(LP)

• Storage: Large works on tracing paper may require rolled or folded storage; this may cause problems of access, especially when the support is deteriorated. The ends of the rolls are often damaged.

Treatment Observations

• In the case of tracing papers that have impregnating agents, treatments can interfere with the original appearance and remove material evidence. Some solvents may cause loss of translucency on some papers as a breakdown of impregnating agents (Baker, van der Reyden, Ravenal 1989, 10). It is suggested that treatments to these types of papers should be kept to a minimum. Conversely, natural tracing papers that have been transparentized by extensive beating of the fibers can withstand extensive treatment (e.g., washing, bleaching, etc.) and will dry without alteration to the surface.(SB)

• Modern natural tracing paper is much stronger than one might expect. It can be manipulated when wet, if it is well supported. Soaking in water does not always completely relax creases, but it may to the extent that the work can be flattened. The object may also be relaxed until limp using vapor from an ultrasonic humidifier.(NA)

• Mending with Japanese paper and wheat starch paste and/or methyl cellulose is usually very successful but, because of the tendency to distort with moisture, only small areas should be worked on at a time. Heat-set tissue (e.g., Rhoplex on paper base) and BEVA mends have also been used. A slight change in appearance may be considered acceptable since it is often unavoidable. The Library of Congress (LC) heat-set tissue works on some tracing papers and when applied with ethanol rather than heat or in combination with heat is almost invisible. More invisible mends can be obtained with a “gossamer tissue” coated with Klucel G developed by F. Mowery. (On the other hand, the Mowery tissue does not offer as much support as the LC tissue.[CS]) Tissue with BEVA 371 or Klucel G applied using solvent instead of heat works well.(CS) The challenge of making mends, fills, etc. unobtrusive may be met by using the optical properties provided by placing a sheet of opaque paper or mat board behind the tracing paper.(SP)

• Backing methods include the use of traditional “wet lining,” heat-activated systems, and solvent activated systems. (See Bachmann 1983 for a summary of the literature to that date.) For the wet lining of nineteenth century tracings, thin Japanese machine made roll papers and very dilute wheat starch paste are recommended; both tracing and roll papers have the same dimensional properties (Nicholson and Page 1988).

• Be aware that solvent treatments on impregnated papers (especially with ethanol and acetone) may alter original tracing paper.(SP)

• Drying and flattening are very important treatment steps for most tracing paper supports which are thin and dimensionally unstable. Successful methods may include the following.

Flattening with considerable weight between hard surfaces (e.g., rag board) has been successful.(NA)

Stretch drying on a screen (mizubari or karibari): moisture and friction bind the primary support between a protective wet-strength tissue on the face and false backing of a suitable Japanese paper; a line of paste is then applied around the extended edges of the Japanese paper. The object is adhered, face inward, by the pasted edges to a Japanese drying screen (also called karibari) or other board. Once dry, the object is dismounted and the false backing and protective tissue are peeled away (Keyes 1984, 101–102; Futernick 1984, 68). Not suitable for objects that are weak, brittle, or damaged by tears or weak fold lines.

• Friction mounting: Combines the use of a false backing (described above) with pressing in a press or between plate glass sheets and under weights. Far less moisture and friction contact are required in this method so that moisture can be reduced to a minimum for vulnerable objects. “Vapor humidification in a chamber or contact humidification between moist blotting paper provides enough moisture for successful friction mounting” (Keyes 1984, 102–104; Fletcher and Walsh 1979, 122–124). Friction mounting may also be undertaken without using a press; sometimes thick felts will provide adequate pressure. (SRA) Felts are useful because they conform to the surface irregularities of sharp creases often present in tissue paper which has previously been folded. (SP)

In all cases it is important to match the grain directions of the original support and the secondary mounting papers.

Friction mounting variation: Place a totally relaxed object face-down onto glass; smooth, thin porous Hollytex on top of object; a blotter extending beyond the glass above the Hollytex; glass and weights. The protruding blotter allows moisture to be removed from sandwich without need to open package risking the formation of cockles. (CS)

Drying against Mylar or Parafilm to encourage a smooth surface. Watch for mirroring.

Some transparent papers can be successfully flattened on the vacuum suction table after first thoroughly humidifying them. Care must be taken to avoid “blotter impression” on these thin papers. (CIM)

• Hinging: See Matting and Framing. One successful method for hinging lightweight papers is to make tiny cuts in the “attachment edge” of the hinge and remove alternate segments, creating a “tiny comb.” Paste only 1 mm of the comb and attach it to the object. Attach hinge to back board 5 mm above the top edge of the object. This method solves the problems posed by the transparency and dimensional instability of tissue and tracing papers (Futernick 1984, 68–69). An alternate hinging method uses hinges made of Hollytex Lite prepared with dilute Lascaux 498–20x or 498–HV which can be reactivated with appropriate solvents or with heat. (AM) Non-impregnated tissue paper may be hinged by application of heat-set tissue and detached with solvent. (SP) For tracing and other papers that are very slick, very calendered, etc., small squares of double-sided tape may be used instead of traditional hinges. This has mainly been for exhibition purposes: the tape has been easily removed after a few years, however long-term stability, etc. is unclear. (KDB)

• Polyester film (Mylar) encapsulation is also a satisfactory way to support tracing paper inside mats. Encapsulation provides physical support, however, be aware that Mylar has strong electrostatic properties and that tracing paper may be torn easily while working. Encapsulation is not recommended for tracing paper with graphite media. (SP)

• Preserve through environmental control. House in special mats to prevent mishandling. Matting these papers can create great danger; the paper can be sucked upwards with the opening of the mat. See Matting and Framing

• Transparentizing material is original and its removal is ethically, as well as practically, questionable. Solvent extraction of transparentizing material such as oils is a debatable treatment, which can remove darkened oils but leave paper opaque. (KN) The paper after oil extraction may be discolored and embrittled. (TF) Removal of transparentizing materials is sometimes necessary if the image is to become visible again. Have high-quality photographs made before extraction. Explore the possibility of adding an archival quality impregnate after removal of the discolored one. (CS)

Cardboard/Artists' Board/Illustration Board

See Backing Removal.

A board 0.006" or more in thickness. It is stiffer than paper (Roberts and Etherington 1982, 47). The term “cardboard” was not generally used until the nineteenth century (Krill 1987, 55).

Pasteboard

In use for bookbinding boards in the late fifteenth century; found on aldine bindings and may have been introduced into Europe from the Islamic world via Venice, Italy. The papermaker can make pasteboards by couching a number of sheets together and pressing, or by laminating several sheets of paper, either of the same size or smaller sheets pieced together. White paper could be used throughout or only on the outer surfaces of the board. Uses include book boards, playing cards, primary supports for drawing and oil paintings, and secondary supports for vellum in miniature painting.

Bristol Board

Introduced in England by 1800 it was a glazed pasteboard made of a fine wove drawing paper. “Each board was embossed with a circle containing the Royal Crown and the words ‘Bristol Paper’” (Krill 1987, 139–141, figs. 121, 122). Used for making cardboard boxes, screens, and as a support for watercolors. Today the term refers to laminates thinner than “cardboard.” (CS)

London Board

A more expensive board made by the 1830s from Whatman's finest drawing paper (Krill 1987 140, fig. 123).

Ivory Paper

A support for drawing introduced in the mideighteenth century and not very popular. It is a pasteboard composed of six sheets of drawing paper with parchment size adhesive between the layers. When dry, the board was smoothed with abrasive papers, coated with plaster of Paris in gelatin, and smoothed again (Krill 1987, 141).

Pulp Paper Boards

• Millboard: Term first used in the very late seventeenth century. These boards were made of the same fibers as pasteboard, but were manufactured by casting on a mold in a single sheet and then milled or rolled under pressure (Krill 1987, 55).

• Strawboard: A very coarse board that contains particulate filler - often lumps of gritty material, like gravel. (AM)

• Rope Manila Board: A very durable pulp board.

• Illustration Board: This commercially available product typically consists of a good quality facing paper upon which the drawing, watercolor, etc. is made; the facing paper is mounted to a cast core board of lesser quality stock. The back of the board may also be faced with a layer of paper bearing a printed inscription identifying the manufacturer, brand name, and a company address that may help in dating the object. “The usual properties of drawing paper, such as finish and sizing, are essential, but hard sizing and good erasing quality are of greatest importance” (Roberts and Etherington 1982, 136).

• Coated Boards (See (Coated Papers.)

Inherent Problems

• Delamination of pasteboards, especially at the corners and around the edges, is a common problem. There is also a tendency to separate when damp. Breakage due to the combination of acidity and inflexibility may also occur.

• Early pulp boards tend to be soft and spongy.

• Thick boards may distort with moisture and are difficult to flatten.

• Artists' Illustration Board: Acid migration from a poor quality lignified core board will discolor and embrittle the better quality facing paper which bears the image.

Treatment Observations

• Readhere delaminating pasteboard sheets where desirable.

• Filling losses: Cardboard often has losses with jagged cross-sections. Japanese tissue or blotters can be shaped to fit one layer of the irregular edge of the cardboard and adhered with wheat starch paste. Another layer of paper may be torn to fit into the next shape presented by the object. Repeat until the front of the cardboard is reached. Finally, apply a larger piece of strong tissue over the top of the fill and extend onto the object enough to cover the break line. Tone the laminates or uppermost layers as necessary. (CS)

In some cases, the use of paper pulp may be the best way to fill a jagged loss. “Back” fill with Japanese paper for added strength, especially with corner losses. (CIM)

• Hinging: See Matting and Framing. Hinges attached to the top edge of the artwork may be pushed through slits cut in the back board so that secure attachment can be made on the back of the mat board (Futernick 1984, 69–70). Use a sink mat to create a ledge below the object for it to sit on. Add a “fence” to the other three sides so they protect against swinging of the heavy object and against physical damage to the laminate edges.

• One must consider the importance of the board to the historic/artistic integrity of the object versus the need to remove the board for the long-term preservation of the image and/or primary support. Separation of the primary support from the secondary core if necessary/possible is tedious, difficult, and time consuming. The loss of structural integrity to illustration board may be offset by the risk to a thin primary support by an embrittled secondary support. See Backing Removal.

Drawing Papers

“The term ‘drawing’ paper was rarely seen in artists' manuals before the end of the eighteenth century...it was not until the 1790s that artists regularly began to use it” (Krill 1987, 83). Gainsborough and other artists used writing paper, which was well-sized, despite its laid lines and glazing, for watercolor or ink (Krill 1987, 83). “For works requiring careful detail, a glazed paper was more suitable...Baskerville had been glazing [between two steel rollers] both printed...and unprinted paper, especially writing paper since the 1750s” (Krill 1987, 89). John Hassell, writing in 1809, recommended two drawing papers - Whatman's wove and Dutch Cartridge. The latter “had a ‘rough tooth’ and was ‘much in vogue’...was a large thick paper and of better quality than the coarser papers used by Girtin [cartridge]. Though it was usually white...it also could be made of mixed furnish.” Dutch Cartridge was still used around 1870 (Krill 1987, 85–86). Whatman's wove paper is also mentioned in Watercolor Papers; Cartridge paper is mentioned in Watercolor Papers and described more fully in Printing Papers.)

East Asian papers: Soft-sized or waterleaf papers were also used for drawing when an artist wanted a more diffuse, less detailed, less contrasting image that allowed the media to blend with the paper. (AD)

Watercolor Papers

A thickish and uniquely hard-sized wove paper; the ascent of the British watercolor school is attributed in part to the development of wove paper by James Whatman in the late eighteenth century. It was considered “the best and proper paper for all serious efforts” (Cohn 1977, 18). English papers used for watercolor before Whatman's development were more weakly sized which made manipulation of the medium difficult because the paper surface would abrade easily. Sizing instructions appeared in artists' manuals. The Art of Drawing and Painting in Watercolors (1778) gave a recipe for sizing paper which was a combination of alum and roch-alum (Krill 1987, 84). Whatman paper was sized to minimize dimensional change when wet and to provide a durable surface that could be manipulated by scraping, rubbing, sponging, wiping, rewashing, etc., without becoming abraded. Paper made from linen rags was thought to withstand these techniques better than paper made from cotton (Cohn 1977, 22).

An even surface was desired for painting. An acceptable range of surface textures, available by 1850, included hot-pressed – a smooth, relatively non-absorbent surface, the intermediate “NOT” (i.e., not hot-pressed), and cold-pressed – a softer, rougher and more absorbent surface. The tooth is particularly important for watercolor; its slight irregularity “...enhanced the reflection of light and added to the vibrancy and luminosity of the washes” (Krill 1987, 89). Manual writers stressed the importance of texture to produce effects peculiar to watercolor (Cohn 1977, 16).

Other desirable properties include consistent absorption properties – the paper should be only slightly absorptive in the short run or the colors will “sink” and become dull, washes do not run smoothly on unabsorptive papers but tend to coalesce into droplets; ideally the paper was white so that light would be reflected through the layers of color and provide the highlights of the design where there was no media. “These requirements were not fully met by paper available before the end of the eighteenth century” (Cohn 1977, 16).

Other papers offered artists qualities of color, texture and sizing that suited their needs: “Cox's” paper, “sugar paper,” Cartridge, Creswick, Harding, Griffin Antiquarian, etc. are some examples (Cohn 1977, 19). To eliminate the need for stretching by the artist in preparation for use, some commercial watercolor sheets are made of a high quality paper mounted on cardboard and often backed with another paper sheet (see Cardboard/Artists' Board/Illustration Board).

Addition of glass fibers and/or a blend of rag and synthetic fibers increase the dimensional stability of some modern papers.

Other supports for watercolor include East Asian papers, “unsized in the Western sense,” which were used in the West to obtain distinctive effects (Cohn 1977, 17); Japanese vellum papers (see Japanese Papers); silk and linen; and colored papers. Machine made papers may be manufactured in imitation of handmade watercolor papers (Cohn 1977, 22; see also Inherent Physical Characteristics of Paper: Surface Texture).

Inherent Problems

• Commercial watercolor board: Survival of the facing paper depends on the quality of the core. Acidity from the cardboard core can migrate to the facing paper, causing embrittlement and discoloration. See Cardboard/Artists' Board/Illustration Board.

• Casual selection of watercolor papers by some twentieth century artists practically guarantees the use of machine made paper, sized with alum-rosin. See Alum-Rosin Sized Papers.

• The potential for cockling is a characteristic of all papers; it is usually a function of the thickness of a sheet (see Thickness under (Inherent Physical Characteristics of Paper) with thinner papers being more susceptible.

Treatment Observations

• Distortion of technical evidence with change in dimensions during aqueous treatments: the size of a watercolor, taken before treatment, may be a fraction of an inch larger than the standard dimensions of nineteenth and twentieth century commercially available watercolor papers. “By wetting and stretching individual sheets prior to painting, the artist would inadvertently increase their dimensions by as much as one-half inch, a size they retained when freed from stretching” (Walsh 1987, 54). Further change may result depending on drying/flattening methods selected.

• Alteration of original technical evidence can result from flattening of cockling that occurred during execution of the watercolor. (NA)

• Technical evidence may also be lost when remnants of “watercolor block” binding material along the outer edges of a sheet are inadvertently removed in treatment, or if a secondary board mount, to which the primary support was attached before execution of the watercolor, is removed since brush strokes often extend over the paper edge onto the board. (NA)

• Washing and drying treatments can increase/decrease the surface texture of some watercolor papers if not accomplished carefully by an experienced conservator.

Artists' Printing Papers

Rag paper

Artists used papers made of rag fibers from early times as supports for prints. These could be strong enough “to withstand dampening and printing under great pressure. (The) surface (was) receptive to ink, neither too rough nor too hard...(They) tended to change color very little with age, mellowing only from white to warm creamy tones” (Boston Museum of Fine Arts 1969, 178). The finest qualities of rag paper could give brilliant impressions with fine detail that was very legible. By the later nineteenth century Lalanne (1880, 72) noted the preference of “most people” for heavy Dutch handmade papers for etchings; charcoal paper and other good drawing papers also sufficed. The laid texture of paper broke up the line, giving highlights within it (Lalanne 1880, 59). Old papers with “brown and dingy edges” were sometimes prized by later nineteenth century printmakers (Lalanne 1880, 59). Because the “sizing has decayed in old papers and the fiber, in consequence, regained its pliability...these take an impression so much more sympathetically” (Lumsden 1924, 139). Lumsden also remarks on the “subtle color” of old paper (Lumsden 1924, 139). For him, soft-sized paper makes the best etching paper; waterleaf paper is “entirely undersized.” Most drawing and etching papers are heavily sized (Lumsden 1924, 139). For mezzotint paper English printers in the nineteenth century preferred the French laid paper that was of hammer beaten linen fiber. (AD)

Plate paper/copper-plate paper

Used for printing from copper plates, it was relatively soft, even surfaced (a result of the use of the wove mold, available late 18th century), free of flaws and absorbent, with little or no sizing (eighteenth century: generally soft-sized; nineteenth century: often unsized). Softness was obtained by reducing sizing and by adding more pliable cotton fibers to the linen furnish. This became common in the early nineteenth century as cotton became more abundant. A thickish paper is required for printing from copper plates; it is too easy to damage the sheet in printing if it is both thin and soft (Krill 1987, 68, 77). During the early nineteenth century “the English vatmen would form each sheet with two layers of pulp - one of ordinary consistency and then, on the side of the sheet destined to take the impression, a second extremely thin layer of especially fine pulp, completely free of foreign matter” (Dyson 1984, 166). Nineteenth century etchers used plate paper to assess the appearance of a plate as it developed; the artist would then usually select a finer paper to print an edition. Artists' manuals described “plain white plate paper” as the worst support for etchings “because (it is the) most inartistic” (Lalanne 1880, 72). Degas, however, frequently printed his etchings on plate paper possibly because of “its effectiveness in rendering the tonal qualities he sought” (Perkinson 1984, 255). Plate paper was often used as a support for nineteenth century chine collé prints published in large editions. (KN)

Oatmeal or Cartridge paper

A cheap, rough, grayish-brown European paper with small flecks in it, made from the leavings of the vat. Oatmeal paper contained a high proportion of unmacerated and varicolored fibers, bits of string, fiber clumps and chips of wood or straw (Robison 1977, 9). Oatmeal seems to be a general descriptive name used by curators to describe a thick coarse paper flecked with dark fibers. (KN) This paper was not made as an art, writing or printing paper, though artists appreciated its texture and appearance. It was used by Rembrandt, for example, on several occasions (Boston Museum of Fine Arts 1969, 180). Oatmeal paper offers a middle range of values; impressions “have a softer, more delicate tonal effect...with a far less stark contrast than...impressions on white (rag) paper” (White 1969, 14). It appears to be a type of utilitarian paper, commonly called cartridge paper, and used to make paper wrappings for rifle cartridges, hence the name. (KN) Today “cartridge paper” refers to a tough, closely formed paper, usually produced from chemical wood pulps and/or esparto. Sizing and surface characteristics depend on intended use (Roberts and Etherington 1982, 47).

Vellum

Etchings and engravings printed on vellum were a rare occurrence in seventeenth century Holland except for Rembrandt's work (Boston Museum of Fine Arts 1969, 180); however, earlier Dutch prints on vellum do exist. In seventeenth century France, portraits were occasionally printed on vellum. With the revival of interest in unusual support materials in the mid-nineteenth century, vellum was again used (e.g., Félix Buhot). Vellum is an unabsorbent material; ink is held on the “almost glassy” surface and does not penetrate at all. Ink tends to “bleed outward over the surface, thus fusing neighboring lines” (Robison 1977, 15).

Imitation vellum was manufactured in the late 19th century since interest in vellum exceeded supply. It was used for “appropriate tonal impressions (and) reproduced the color and transparency and even the slick, slightly ‘glassy’ surface texture of the real skins” (Robison 1977, 15). For a general description of vellum as a support material see Parchment/Vellum.

India paper

Also known as India, India proof, India transfer paper

According to Labarre (1937, 160) this is really China paper. The name is an English term that may be a misnomer derived from its having been imported by the Dutch East India Company. (KN) The name is sometimes loosely given to other papers of Asian origin, but also to papers of European and American manufacture (Labarre 1937, 160).

An off-white paper, varying in tone, without prominent laid lines but with yellow fibers throughout. This soft, unsized paper “adapts itself to the surface of the steel plate or wood, and soaks up a large quantity of ink without afterwards smearing” (R. Perkinson, A Treatise on Paper, London 1894 as quoted by Labarre 1937, 160). Thought to have been used by Rembrandt for several impressions, this paper is very absorbent and gives rich soft effects, particularly suited to the qualities of drypoint (Boston Museum of Fine Arts 1969, 180). Mentioned by Lalanne (1880, 59) as promoting “purity of line.” India paper has been a thin, opaque paper made from chemically processed hemp and rags since 1875 (Roberts and Etherington 1982, 138). The British successfully imitated this paper with “Oxford India,” a very white paper which somewhat resembled Western cigarette paper (also called “Cambridge” and “Bible”) (Dwan 1989).

Japanese papers

First imported into Europe in quantity in the seventeenth century. When printed, this smooth paper “receives the ink very well from the plate, but instead of absorbing the ink into the substance of the paper like European sheets, Rembrandt's Japanese paper holds the ink on the surface, keeping it all there and fully visible” (Robison 1977, 13 referring to Rembrandt's use of Japanese paper). The polished, soft surface “receives ink readily under minimum pressure and so does not wear down fine drypoint lines and burr as quickly as rougher paper surfaces tend to do” (Boston Museum of Fine Arts 1969, 180). It was also capable of taking very rich impressions. Lalanne notes the excellent qualities of Japanese paper which is “...of a warm yellowish tint, silky and transparent, is excellent, especially for plates which need more of mystery than of brilliancy, for heavy and deep tones, for concentration of effect...”(Lalanne 1880, 60). Lumsden (1924, 139) also noted its beauty of color. In the nineteenth century, Whistler made abundant use of a variety of Japanese papers. Gampi was preferred by 19th century European wood engravers because it allowed them to achieve the finest detail (e.g., A. Lepère). For a general description of Japanese papers as support materials see Japanese Papers.

Inherent Problems

• Plate paper/copper plate paper is vulnerable to mold and foxing stains. Grime is easily embedded into the paper surface.

• Vellum has a very nonabsorbent, glossy printing surface. The printing ink may not penetrate the surface resulting in flaking of the media, particularly with fluctuations in ambient relative humidity/moisture content. Ink may be easily abraded, especially at the high points of a cockled sheet.

• Japanese Papers: Gauguin is known to have printed some woodblocks in black ink on a support paper, and then covered the support (and printed image) with a thin tengujo (kozo) veil. He recut and printed the block on top of the tengujo. It is almost impossible to see but important to know about before treatment (Dwan 1989, 9).

Nineteenth century prints on Japanese papers often show a shiny, burnished area from contact with the metal plate during printing; this contrasts beautifully with the matte, unprinted and unpressed margins. The burnished area can easily be damaged by abrasion, distortion, or swelling during aqueous treatments (Dwan 1989).

Treatment Variations

• Plate paper/copper plate paper: Dry cleaning may be difficult. Plate impression may be lost during treatment. (AD) Crisp, fresh plate impressions in particular may be affected. However, sometimes a squashed or barely visible platemark may be revived somewhat through aqueous treatment. (NA)

• Blind stamps, printers' chops, and other embossed marks can be reduced in crispness during aqueous treatment. The finer and more detailed the stamp, the greater the tendency toward softening of detail. (NA)

References

Mechanical Wood Pulp Papers

Hon, David N.S. "Discoloration and Deterioration of Modern Papers." Science and Technology in the Service of Conservation, Preprints of Contributions to the IIC-Washington Congress. London: IIC, 1982.

Lyall, Jan. "A Preliminary Study of Chemical Methods for Stabilizing Lignin in Groundwood Paper." Science and Technology in the Service of Conservation, Preprints of Contributions to the IIC-Washington Congress. London: IIC, 1982, pp. 79-84.

Shahani, D.J. "Options in Polyester Encapsulation." Association of Canadian Archivist Bulletin 2, No. 1, 1986, 1 page.

Young, G.S. and Helen Burgess. "Lignin in a Paperboard Advertised as Lignin-free." IIC-CG Bulletin 14, No. 4, 1989, pp. 14-16.

Colored Papers

Perkinson, Roy. "Observations in the Drawings of Winslow Homer." The Book and Paper Group Annual 5, 1986, pp. 1-8.

Samuels, Laurie. "Optical Brighteners in Paper." Papers Presented at the 15th Annual Art Conservation Training Programs Conference. Harvard University Art Museums, 1989, in press.

van der Reyden, Dianne and Nancy McRaney. Identification of Colorants for Paper. Smithsonian Institution, Conservation Analytical Laboratory: Washington, D.C., 1990, unpublished.

Blue Papers

Adam, E. and Sullivan, M. 2024. Drawing on blue: European drawings on blue paper, 1400s–1700s. Getty Publications.

Bescoby, J. and Raynor, J. 2010. "Supports and Preparations" in Italian Renaissance Drawings, Technical Examination and Analysis. Archetype Publications. London. pp. 17-21.

Bower, P. 2002. "Blues and Browns and Drabs: The Evolution of Colored Papers" in The Broad Spectrum, Studies in the Materials, Techniques and Conservation of Color on Paper. Archetype Publications. London. pp. 42-48.

Brückle, I. 1993. "The Historical Manufacture of Blue-Coloured Paper". The Paper Conservator Vol. 17, No. 1. p. 20-31. DOI: 10.1080/03094227.1993.9638402.

H. Charbey, Investigation sur les papiers bleus en Europe Occidentale des origines à la fin du 18eme siècle, Thesis, lnstitut Français de Restauration des Œuvres &Art, Paris, 1989.

Higgitt, C. "Drawings in the Renaissance Workshop" in Italian Renaissance Drawings, Technical Examination and Analysis, Archetype Publications, London, 2010, pp. 17-21.

Kim, H. and Kim, H.-B. 2000. "New Evaluation Method for the Lightfastness of Colored Papers by Radiant Energy". Journal of the Illuminating Engineering Society, Vol. 29, No.1. pp. 17-24. DOI: 10.1080/00994480.2000.10748477.

Levison, H. W. et al. 1987. "Lightfastness of Pigmented Handmade Papers". Color, research and application. Vol 12, No. 1. pp. 37-41. DOI: 10.1002/col.5080120107

Messager, M. and Rouchon, V. 2013. "Damaged Blue Papers: Optimising Consolidation while Preserving Original Colour. " Journal of Paper Conservation. Vol. 14, No. 2. pp. 9-19. https://doi.org/10.1080/20571682.2013.12462322.

N. Tello-Burgos, N. et al. 2020. "Identification of Indigo Dye (Indigofera tinctoria) and Its Degradation Products by Separation and Spectroscopic Techniques on Historic Documents and Textile Fibers". Studies in Conservation, pp. 1-16. DOI: 10.1080/00393630.2020.1796019.

Perkinson, R. 1997. "Summary of the History of Blue Paper". The Book and Paper Group. Vol. 16 (Fall 1997).

Rearick, W. R. 2004. "The Study of Venetian Drawings Today". Master Drawings. Vol. 42, No. 4. Venetian Drawings (Winter 2004). pp. 299-301.

Loaded Papers

Daniels, Vincent. "A Study of the Crystallinity of Paper Before and After Conservation." The Paper Conservator 10, 1986, pp. 70-72.

Artists' Coated (Prepared)

Cennini, C. The Craftsman's Handbook. Translated by D. Thompson, Jr. New York: Dover Publications, Inc., 1954, pp. 6-7.

DaVinci, Leonardo. Treatise on Painting. Translated by P. McMahon. Princeton: Princeton University Press, 1956, p. 105.

Ellis, Margaret Holben. "Metalpoint Drawings: Special Problems for Collectors." Drawing 2, No. 3, 1980, pp. 59-61.

Richmond, Alison, "Turner's Use of Paper up to 1820' - A talk given by Peter Bowers." Paper Conservation News, No. 54, 1990, p. 4.

Coated Papers

Baker, M., D. van der Reyden, and N. Ravenal. "FTIR Analysis of Coated Papers." The Book and Paper Group Annual 8, Washington, DC: AIC, 1989, pp. 1-12

Casey, James P., ed. "Pigment Coating." Pulp and Paper: Chemistry and Chemical Technology. New York: John Wiley and Sons, Vol. 4., 1983 "Pigment Coating," pp. 2018-2189.

Parker, A.E. "The Freeze-Drying Process: Some Conclusions." Library Conservation News, No. 23, 1989, pp. 4-6, 8.

Prosser, Ruth. "Pigment Coated Printing Papers." Modern Art: The Restoration and Techniques of Modern Paper and Prints. London: UKIC, 1989, pp. 8-12.

Lattuati-Derieux, A., Egasse, C., Regert, M., Chung, Y., Lavédrine, B., 2009. “Characterization and degradation pathways of ancient Korean waxed papers”, Journal of Cultural Heritage, Vol 10, pp. 422–427.

A collection of Korean waxed papers from the 15th-16th centuries were chosen to be studied because they were starting to present signs of deterioration. These included: traces of mould, folds, cracks, embrittlement of the wax and white or purple deposits on the surface. The authors of this paper used Fourier Transform Infrared (FT-IR) spectra and gas chromatographic and mass spectrometry investigations to identify the biomarkers and degradation markers of the Korean paper samples. Four different samples of waxed paper were taken. Comparing the samples to a modern sample of Korean beeswax showed that the chemical composition was very similar to the ancient Korean beeswax samples found on the papers. The main degradation compounds were found to be hydroxyethers.

Tissue/Tracing Papers

Anderson, Priscilla. "Transparent Paper: An Examination of its Uses Through Two Centuries." Senior essay, History of Art Department, Yale University, New Haven, Connecticut, 1990

Bachmann, K. "Transparent Papers Before 1850: History and Conservation Problems." New Directions in Paper Conservation. The Institute of Paper Conservation 10th Anniversary Conference, Conference Notes. Oxford, England: Institute of Paper Conservation, 1986, p. D61 (abstract).

Flamm, Verena, Christa Hofmann, Sebastian Dobrusskin, and Gerhard Banik. "Conservation of Tracing Papers." 9th Triennial Meeting of the ICOM Committee for Conservation Preprints. Dresden, German Democratic Republic: ICOM, in press 1990.

Fletcher, Shelly and Judy Walsh. "The Treatment of Three Prints by Whistler on Fine Japanese Tissue." Journal of the American Institute for Conservation, 18, No. 2, 1979, 118-126.

Futernick, Robert. "Methods and Makeshift: Stretch Drying Lined Artifacts." The Book and Paper Group Annual 3, Washington DC: AIC, 1984, pp. 68-70.

Keyes, Keiko M. "The Use of Friction Mounting as an Aid to Pressing Works on Paper." The Book and Paper Group Annual 3. Washington DC: AIC, 1984, pp. 101-104.

Mills, John S. "Analysis of Some 19th Century Tracing Paper Impregnates and 18th Century Globe Varnishes." New Directions in Paper Conservation. Oxford, England: Institute of Paper Conservation, 1986.

Priest, Derek. "Paper Conservation Science at UMIST." The Paper Conservator 11, 1987, pp. 73-80.

Rundle, C. "The Composition and Manufacture of Modern Tracing Papers." New Directions in Paper Conservation. Oxford, England; Institute of Paper Conservation, 1986, D64-65 (abstract).

Wilson, Helen. "A decision framework for the preservation of transparent papers." Journal of the Institute of Conservation. 38, No. 1, 2015, 118-126. Online here

Yates, Sally Ann. "The Conservation of 19th Century Tracing Paper." The Paper Conservator 8, 1984, pp. 20-39

Includes short bibliography of publications containing useful information on tracing paper.

Cardboard/Artist's Board/Illustration Board

Futernick, Robert. "Methods and Makeshift: Hinging Artifacts to Matboard." The Book and Paper Group Annual 3, Washington DC: AIC, 1984, pp. 68-70.

Gould, Barbara. "The Removal of Secondary Supports from Works of Art on Paper." The Book and Paper Group Annual 6, 1987.

Keyes, K. M. "A Method of Conserving a Work of Art on a Deteriorated Thin Surface Laminate." The Paper Conservator 10, 1986, pp. 10-17.

Watercolor Papers

Cohn, Marjorie. Wash and Gouache: A Study of the Development of the Materials of Watercolor. Cambridge, MA: The Center for Conservation and Technical Studies, Fogg Art Museum, 1977.

Walsh, Judith. "Observations on the Watercolor Techniques of Homer and Sargent." American Traditions in Watercolor: The Worcester Art Museum Collection. Susan E. Stickler, ed. New York: Abbeville Press, 1987, pp. 44-65.

Artists' Printing Papers

Dyson, A. Pictures to Print: The 19th Century Engraving Trade. London: Farrand Press, 1984.

Lalanne, Maxime. A Treatise on Etching. London: Sampson Law, Marston, Searle and Rivington, London, 1880.

Lumsden, E.S. The Art of Etching. New York: Dover, 1924.

Perkinson, Roy. "Degas's Printing Papers." Edgar Degas: The Painter as Printmaker. Sue Walsh Reed and Barbara Stern Shaprio. Boston: Little, Brown and Company, 1984, pp. 255-261.

Robison, Andrew. Paper in Prints. Washington, DC: National Gallery of Art, 1977.

White, C. Rembrandt as an Etcher London: Zwemmer, 1969.

History of this Page

This page was created in April 2025 by Sandrine Blais from the BPG Support Problems page.