Mending (PCC)

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Mending paper is done by locally joining splits or tears or reinforcing cracks in a paper support using an adhesive material. The purpose is to restore aesthetic unity of the sheet and to preserve its physical integrity.

Original Compilers: Nancy E. Ash, Kitty Nicholson
For a full list of the original contributors to this page, see the section below on History of this Chapter.
Wiki Contributors: Clare Manias, Emily Williams, your name could be here

Copyright 2018. The Book and Paper Group Wiki is a publication of the Book and Paper Group of the American Institute for Conservation of Historic and Artistic Works. It is published as a convenience for the members of the Book and Paper Group. Publication does not endorse nor recommend any treatments, methods, or techniques described herein. There is an ongoing project to update the BPG Wiki. We welcome contributions and feedback. If you would like to get involved in this effort, please contact the wiki team at [email protected].

Factors to Consider


Character of the paper: weight, strength, absorbency, texture, color.

Nature and location of the tear: puncture, slit, overlap, straight, forked; at edge, in image

Media condition and characteristics: possible problems with moisture, manipulation, placing face down


Materials and Equipment

Adhesives

Chosen for flexibility, strength, non-contractibility, non-darkening and long term good aging characteristics and reversibility. For specific adhesives see Adhesives for Paper and BPG Adhesive Recipes and Tips.

Aqueous Adhesives

Can be applied directly to tear edges and/or applied to a reinforcing paper strip.
Starch Pastes Wheat or rice are in common use. Also potato, cornstarch, arrowroot.
Cellulose Ethers Methyl cellulose, carboxy methyl cellose are in common use. Also hydroxy ethyl cellulose, hydroxy propyl cellulose.
Proteinaceous Adhesives Gelatine, parchment size. For possible use with parchment (likely to darken or discolor paper).

Non-Aqueous Adhesives

Are applied to a carrier to make heat set or pressure sensitive mends.
Acrylic Emulsions (e.g. Rhoplex, Plextol)
EVA Emulsions (e.g. Elvace)
PVA Resin (e.g. Hot Melt, PVA, AYAA + AYAC).
BEVA 371

  • Heat Set
  • Webbed for pressure sensitive application by spraying with compressor. BEVA will gel before contacting reinforcing paper.

Commercially Preparations
(e.g. Filmoplast or Promatco adhesives) Sometimes used by conservators for temporary mends. A danger lies in not knowing all ingredients in proprietary formulations.

Reinforcing Paper Strips

A reinforcing paper strip with applied adhesive generally forms the mending material. Considerations: weight, strength and quality of reinforcing paper material; width of strip; whether paper reinforcement is needed at all.

Japanese Tissue Paper

is chosen for its freedom from impurities, flexibility, and long fibers. A particular tissue is selected for its compatibility to the design support paper (generally the tissue is lighter weight).

  • Very Thin (e.g. gampi, tosa, tengujo).
  • Thin (e.g. kizukishi, kanaryoshi, udagami).
  • Medium (e.g. sekeishu).
  • Heavy (e.g. okawara, uda).


Lens Tissue

is short fibered and not very strong. It can be used when fiber length is not critical. It is most often used with non-aqueous adhesives.

Materials and Equipment for Preparation and Application of Mend

Surface to paste out on

  • Smooth surface with good release properties (e.g. polyester film, silicone release paper).
  • Absorbent surface (e.g. blotters).

Brushes to apply paste

  • Stiff, short bristled for controlled application of thin adhesive layer to reinforcing strip and for ensuring firm contact between mend and support.
  • Thin, soft, pointed for applying adhesive to tear edges.
  • Stipple brush for tapping mends into place.

Tweezers

Light box

Materials and Equipment for Drying and Flattening Mend

Blotters to draw moisture out of mend.

Release material silicone release paper, polyester web, polyester film. Generally placed between blotter and wet mend to prevent sticking.

Air gun, tacking iron for faster drying.

Weights, plexiglas, glass, blotters, felts for flattening.

Treatment Variations

Conventional Mending with Aqueous Adhesives

Object should be cleaned prior to mending with care taken to clean in and around the area to be mended. Adhesive application, especially aqueous, will set grime and may emphasize tear edges. (See: Surface Cleaning; Washing: Local Treatment Methods)

If tear remains soiled, some conservators recommend teasing out fibers along tear edges. A needle point can be used to soften and feather edges which are hard, dirty or encrusted with adhesive. For grimey tears that resist all other cleaning some advocate removing the dirtiest edge fibers. Others feel that this compromises the integrity of the support.

As an alternative, overlays of thin paper or pulp may be desired to cover very dirty mends. (See Filling of Losses: pulp fills)

Align Tear

Confirm that both design elements and tear edges match up. Confirm that flaps along tear edges overlap properly.
Placing an object on a light box may help assure that alignment is maintained during mending. Others find it advantageous to align edges and mend, at least initially, with the drawing face up. To mend object face up, a pasted out Japanese tissue strip is tacked with adhesive to a piece of polyester film which is used to maneuver the strip into place beneath the tear. When dry such mends will help hold the tear in alignment for further mending.

Adhere tear edges

Direct application of adhesive to tear edges. The wet adhesive (starch paste or cellulose ether) can be applied directly to tear edges and flaps. Polyester film or other material might be inserted between torn edges to protect the underlying side from adhesive before the actual join is made.

Prepare paper reinforcing strips

  • Grain direction of reinforcing strips
Paper strips can be torn with or against the grain. Considerations: matching grain direction of strips to grain direction of object support; increasing mend strength across a tear by having strip grain perpendicular to tear direction.
  • Torn-edge reinforcing strip
Most common in paper conservation. The feathered edges of the reinforcing strip diffuse the mend boundaries and lessen chances of creating a bulge in the support. They also provide additional strength across the mend.
  • Mending strips with cut edges
When large numbers of tears need mending and when cut edges will not create ridges on the recto, mending strips can be cut with a ruler and scalpel, scissors, etc.
  • Multiple strips are prepared in advance by Japanese mounters.
They take long narrow strips of paper (e.g. 2 by 12 inches) and fold them in half (e.g. 2 by 6 inches). Closely spaced parallel cuts (ca. 5 inches long) are then made in the folded edge, leaving about one inch uncut at the other end. When unfolded the result is many narrow cut strips held together at the ends by one inch bands which can be removed when the strips are needed.

Apply adhesive to reinforcing strips

Adhesive is applied to strip with a stiff brush, brushing outwards from the center of the tissue to splay the fibers.

Adhesive can be brushed onto the reinforcing strip on any smooth inert surface such as polyester. If moisture causes problems to the support, the adhesive can be applied to the strip on a blotter to absorb any excess moisture.

Apply paper reinforcing strip over tear

When the paper strip is applied to the tear, fibers are again brushed outwards to ensure contact.

Scroll type mend: Japanese scroll mounters find it fast and convenient to wrap long pasted repair strips on a spiral around a tool or brush handle, and then to unwind the desired length along a tear or crack.

Drying aqueous adhesive mends

Use blotters to absorb moisture from mend while weighting damp area to prevent cockling of the support and contraction of paste layers. Polyester web or other release materials are important initially to prevent accidental adhesion.

When fast drying is desired, e.g. to prevent water staining or for convenience, use heat from a hot air blower or from a tacking iron applied through a protective cover blotter strip or silicone release paper.

Mending Paper Easily Discolored by Aqueous Adhesives

Proceed as above, but omit step applying paste to tear edges. Tear is only held together by pasted reinforcing strip. This approach might be appropriate for paper that discolors with any direct adhesive application to tear edges.

Mending Tears with Alignment Problems

Align Tear: Some old tear edges may have sprung from uneven expansion and contraction, creating a gaping tear or preventing design elements from meeting correctly.

  1. Manipulate the dry paper into alignment. Sometimes the dry paper can be manipulated into alignment and mends applied gradually, checking alignment as each area is joined and dried.
  2. Hold tear in correct alignment with weights. It may be necessary to realign tear using weights to hold a torn paper in as nearly a correct position as possible while applying adhesive and reinforcing strip, and while mend dries.
  3. Use moisture to locally expand paper. An area which is to be expanded relative to another might be wetted (with brush, moist blotters or spray) and weighted in the expanded position to stretch the paper slightly. The area should be carefully observed to make sure that it is not under excess stress, which can extend the tear or create new tears.
  4. Use heat to locally contract paper. An area which is to be contracted relative to another might be wetted and dried with a warm air gun. A series of such manipulations may help align the tear.
  5. Temporary mends may be needed to maintain the alignment or keep a gap closed in preparation for permanent mends. These mends may use aqueous, pressure-sensitive or heat set adhesives. They are applied at points along a tear to hold it in the correct position while permanent mends are being applied. The mended tear might not lie flat but can be relaxed and flattened locally or overall afterward.
The temporary mend may be applied to the recto (avoiding design areas) or the verso. If placed on the verso, temporary mends are removed before the permanent mend reaches that point. Mends on the recto can be be removed after the entire permanent mend is made, but prior testing should be used to assure that the adhesive in no way alters the surface. Some fear that any adhesive placed on the front surface may alter the long term aging characteristics of the paper in that area.

Mending Tears in Paper with Single Fiber Reinforcements

Single Japanese fibers are useful to bridge tear edges for an object with image on recto and verso. Proceed as above, but omit reinforcing strip. Single fibers of Japanese paper can be teased off with a needle point from a pasted out bit of paper. The slight amount of paste on the fiber will adhere it. Apply so as to bridge tear edges on both or either recto and verso, according to location of design. Fibers can be teased from papers toned with non-aqueous colorants if off-white fibers are too noticeable.

Tab Mend

When verso is not directly accessible, reinforcing strip is inserted from recto to verso. One half of tissue tab is pasted out, inserted beneath one tear edge, pressed into contact, and allowed to dry. The second half is then pasted out (on a protective slip of polyester film) and manipulated beneath the other side of the tear. Particularly useful with three-dimensional or permanently lined objects.

Mending with Internal Reinforcement Strips

Where the paper support is amenable (i.e. a laminate structure) and if it is necessary to camouflage a mend from both sides of an object, the support paper can be split and a pasted reinforcing strip inserted to join the two sides of the tear. The split edges are then readhered to the reinforcing strip and allowed to dry flat.

Closing a Gaping Tear

A tear may pull together if reinforced with a paper such as gampi which contracts greatly as it dries.

Mending a Ridged Tear

Tear edges which lift into a raised ridge can be mended with double-layered repair strips: a narrow strip directly reinforcing the tear, a wider strip overlying the narrow one. Alternately a very contractile reinforcing strip of gampi may pull the edges flat.

Mending a Tear with a Very Thin, Skinned Fap

A non-contracting adhesive such a methyl cellulose (or a 50:50 mixture of paste and methyl cellulose) will help prevent puckering of the thinned flap and is less likely to discolor the thinned area.

Mending with Acrylic Emulsion Heat Set Tissue

Align tear (See Conventional Mending with Aqueous Adhesives)

Prepare reinforcing paper

  1. Coat adhesive chosen onto Japanese paper or lens tissue and allow solvent to evaporate. (See: Hey and Waters for method in use at Library of Congress. This coated paper is also sold by some conservation suppliers.)
  2. Shape coated heat set tissue: Score with stylus and ruler and tear along scored line. Alternatively, wet with acetone, ethanol or other appropriate solvent and then tear along wetted line to create feathered edge. Tissue can also be rolled into a tube and ends sliced off to create strips.

Apply heat set tissue with coated side to surface of object and tack with tacking iron.

Clarify the heat set tissue. Tissue can be made more transparent after application by treating with acetone or ethanol or solvent appropriate to the adhesive system.

Mending with BEVA 371 Heat Set Tissue

Align tear (See Conventional Mending with Aqueous Adhesives)

Shape reinforcement strips prior to coating if feathered edge is desired, otherwise cut coated tissue to shape.

Brush on BEVA diluted to consistency of maple syrup. Allow solvent to evaporate.

Apply uncoated side to object to minimize adhesive penetration of object.

Apply heat sparingly through silicone release paper. Overheating may drive the adhesive into the paper.

Historical Techniques and Materials


Bibliography


(See Adhesives: Bibliography)

Claire, Julian and Frederick Marsh. A Dry Repair Method for Islamic Illuminated Manuscript Leaves,” The Paper Conservator, 4, 1979, pp. 3–9.
Includes toning Japanese tissue with dye; use of lens tissue; use of tacking iron; use of heat set tissue.
Clapp, Anne F. Curatorial Care of Works of Art on Paper, c1973; 3rd. ed., Oberlin: Intermuseum Conservation Association, 1978, pp. 67–69.
Mending edge tears with torn-edge Japanese tissue paper and starch paste.
Hey, Margaret and Peter Waters. Heat-Set Tissue, Library of Congress.
Horton, Carolyn. “Conservation Problems of Audobon's Birds of America, AIC Preprints, 1977, p. 79.
Includes cleaning edge tears.
Johnson, Ben G. “Oriental mounting techniques in the conservation of western prints and drawings,” IIC Preprints, 1972, pp. 517–521.
Includes double- layered mending strips for ridged tears.
Jones, Melvyn. “Traditional Repair of Archival Documents,” The Paper Conservator, 3, 1978, pp. 9–17.
Using lens tissue and paste.
McAusland, Jane. “Facsimile paper repairs for works of art on paper,” The Paper Conservator, 3, 1978, pp. 29–32.
Including paring away dirty tear edges; splitting paper to make internally reinforced tears.
McMullen, Orla. “Paper Repair in Older Printed Books,” The Paper Conservator, 3, 1978, pp. 18–29.
Includes heat set tissue and Japanese tissue and wheat starch paste discussion.
Pataki, Andrea. “Remoistenable Tissue Preparation and its Practical Aspects”, Restaurator, 2009. pp. 51–69.
This article looks at the adhesives used to prepare remoistenable tissues for repairs. The successful adhesives for light-weight tissue repairs were: Gelatin, isinglass, cellulose ethers, starch paste and synthetic adhesives such as Aquazol® and Paraloid B72. Funori and JunFunori® were tested and showed to be unsuitable to make remoistenable tissues. A successful adhesive was judged based on its ability to form an adhesive film, by the concentration it must be made to, by the flexibility of the tissue-adhesive, by the transparency of the adhesive tissue and by the adhesive’s swelling ability, which enables re-activation.
The article also looks at the types of tissues used for repair and their characteristics, as well as looing at the different adhesives in their various concentrations, and how these have an effect on their flexibility and what solvents are needed to reactivate the tissues. These qualities are very important when choosing an adhesive and tissue to make your repairs with. The results are reported in a very clear and easy to read table. Images are used to explain some of the tests that were done, which are also useful to understand the issues or advantages of using certain materials.
Schraubstatter, Carl. Care and Repair of Japanese Prints, c1948; 2nd ed. New York: Asian Conservation Laboratory, 1978.
Stevens, Phillip. “The Conservation of Illuminated Islamic Manuscript Leaves,” The Conservation of Library and Archive Materials and the Graphic Arts. IPC: Cambridge, 1980, pp. 157–160.
Internally reinforced tears inserted between sheets of paper making up the Illumination.
Wardle, D.B. Document Repair, London: Society of Archivists, 1971.

History of This Chapter

BPG Wiki
In 2009, the Foundation of the American Institute for Conservation of Historic and Artistic Works (FAIC) launched the AIC Wiki with funding assistance from the National Center for Preservation Technology and Training (NCPTT), a division of the National Parks Service. Along with catalogs from other specialty groups, the published Paper Conservation Catalog and the unpublished Book Conservation Catalog were transcribed into a Wiki environment. In 2017, Clare Manias reformatted this chapter by removing the legacy numbered outline format and improving internal links.

Paper Conservation Catalog (print edition 1984-1994)
Prior to the creation of the AIC Conservation Wiki, this chapter was created in 1984 as Chapter 25: Mending (PDF) of the 1st edition of the Paper Conservation Catalog, (print edition 1984-1994) by the following:

Compilers: Nancy E. Ash, Kitty Nicholson


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