Conserving Works of Art on Paper

Suggestions from an expert on the care and conservation
of valuable works on paper

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The purpose of paper conservation or restoration work is to preserve and restore works on paper and make them accessible for exhibition, sale or study. Often, the works selected for conservation treatment are aesthetically damaged, too fragile for exhibition, or they are in imminent danger due to continuing deterioration. Each art work has its own history of previous treatment, framing, and environmental exposure, and consequently the conservation and restoration of each individual work presents a unique set of considerations. Galleries, collectors, and picture framers might wish to be aware of some of the terminology, problems, and possible treatments that may be undertaken by a paper conservator.

Flaking media: Consolidation

Some media, due to inherent flaws in the media itself or due to environmental conditions, may start to crack and flake off the paper. Without stabilization, the image will continue to abrade with each handling. Flaking media should be "consolidated." Diluted solutions of the consolidator could be applied locally with a fine brush, feeding the material into the cracks and reattaching the flakes of media to the paper.

Acidic mount: Removal

Acidic cardboard and paper mounts (the acidity is often caused by deterioration of wood pulp fiber in the paper) eventually cause overall darkening and increasing fragility of the paper support because of acid migration from the mount into the original support paper. Acidic mounts may or may not be removed. The severity of the deterioration being caused by the mount must be weighed against the difficulty of removal and any historic significance of the mount. A mount removal might involve delamination of the cardboard by splitting between cardboard layers with a microspatula, then removing the residual paper and adhesive with steam. In certain cases, when the paper support is extremely fragile, after the mount is removed, a new paper lining might be attached using appropriate adhesives.

Tapes, adhesives: Removal

Pressure sensitive tapes (Scotch tape, masking tape), gummed tapes and labels, paper patches, and various adhesives on both the recto and verso of the pictures, will cause stains that eventually migrate through the paper to show on the front. Adhesive residues, tapes, and stains become increasingly difficult to remove or reduce, and may become worse with time. Methods for removal of tapes and stains are necessarily specific to each work. The kind of tape, the type of paper to which the tape is adhered, the length of time the tape has been in contact with the paper, the intrusion of the tape into the design area, and the amount of staining caused by the tape must all be considered. The tapes and residual adhesive may be removed by a number of methods, which include cutting off with a scalpel, lifting off tapes or adhesives after softening with steam or heat, or by local application or immersion in solvents. Adhesives which are still tacky may sometimes simply rolled off with a soft eraser.

Stains: Reduce with solvent

Before any treatment with a solvent is undertaken, very small spot tests on both the paper and the media must be conducted, to ensure that they will remain stable during the procedure used to reduce the stain. The following methods may be used:

  1. Immersion of the entire sheet in a bath of solvent helps to remove the tape (if it has not been previously removed), the surface adhesive, and reduce stains that have migrated into the paper.

  2. A poultice consists of a solvent which dissolves the adhesive and pulls the dissolved substance away from the surface into the absorbent material.

  3. A suction table is a mechanical tool which pulls solvents through the stains to a blotter below.

Stains: Reduce with water

The reasons for immersing a sheet of paper in water are to remove some discoloration, water-soluble stains, and to reduce acidity. The media and the paper must first be spot tested to ensure that no harm will be done by immersion. There are some works of art on paper which could benefit from water treatment, but whose media (watercolors, pastels, charcoal) are such that total immersion could cause some injury. These works may be floated on the surface of the water, or be treated in localized areas using poultices or the suction table.

Stains: Bleach

Stains such as foxing (brown spots caused by molds or my metal impurities left in the paper during manufacture), matburn (the brown line caused by contact with an acidic mat), some water stains, and mold stains may not be removed by immersion in water. If these stains are very disfiguring, it may be appropriate to use one of a variety of bleaching agents that have been thoroughly tested and researched for use on works of art on paper. Sun/light bleaching, and bleaching with chemicals such as hydrogen peroxide or calcium hypochlorite, are possibilities given certain conditions in the media and the paper. Any bleaching should be carried out in a carefully measured and controlled environment and all necessary precautions taken to be sure that any bleaching agent is neutralized or washed from the paper.

Acidic paper: Deacidification

Paper exposed to heat and ultraviolet light, that has been in contact with poor quality materials, or that has a high percentage of wood pulp fiber, may become darkened and brittle. Deacidifying solutions can be introduced into a paper by immersion, or by brushing or spraying on the solution. Both aqueous and non-aqueous solutions are available and deposit an alkaline reserve in the paper. This process helps to

  1. neutralize the accessible acids present

  2. prevent the development of acids in the future

  3. ward off foxing

Tears, losses: Repair

Previously mended tears may stain and distort the paper in the torn area because of badly applied and poor quality adhesives. Old mends should be removed and be replaced with archival repairs. Tears left unrepaired may increase in length, causing more damage as the paper is handled. Lacunae (losses in the paper) which are left unfilled, are subject to the same mechanical stresses as the tears. Tears may be mended with wheat starch paste or methyl cellulose, reinforced with Japanese tissue on the verso as necessary, or with archival heat set tissue. Lacunae may be filled by inserting a patch of paper which is close to the original paper in texture, weight, and color, or with liquid paper pulp. Where the lacunae or tear intrudes into the design, minimal toning of the repair can create a less visually disturbing mend.

Weakened paper: Attach lining

A paper may become weakened through contact with other acidic materials, through inherent flaws in its manufacture, by previous mishandling causing tears and structural weaknesses, or by previous attachment to a poor quality mount. If the paper is extremely fragile, it may be strengthened by lining (backing) the sheet with a high quality Japanese or rag paper adhered with an archival adhesive. The lined work is then dried under slight tension or between blotters under appropriate weight to avoid any cockling or distortion. In cases where the paper or media should not be flexed at all, mounting to an archival secondary solid support may be considered.

Cockling, creases: Flatten

Severe cockling (rippling of paper, usually caused by exposure to moisture) or creases may cause aesthetic or structural problems, and the paper in a creased area may weaken or tear if not reinforced. Cockling and other distortions may cause abrasion of the image in areas which rub against another work stacked above or against glazing material in contact with the paper. Wrinkles and creases may be flattened by local application of moisture to that area, followed by gentle pressure under blotters and weights. When necessary, severe creases may be reinforced on the verso with Japanese paper adhered with an archival paste. Overall cockling of the paper (if not inherent to the work) may necessitate relaxation of the paper with moisture, and subsequent pressing between blotters under weight. If the media is too sensitive for this type of flattening procedure, a special matting arrangement (a more deeply cut window mat) might be helpful in protecting the surface.

Media loss: Inpaint

Where a crease, a tear, a lacuna, or an abrasion intrudes into the image area, an aesthetic decision may be made to tone the missing area to make it less visually disturbing. The method used for inpainting (a term used to define the ethical approach that any toning is in the area of loss only, does not extend into the original media area, and does not alter the aesthetic quality of the work) depends upon the media or the work.

By Patricia Morris is a nationally-known conservator and restorer of art and artifacts on paper who resides in Santa Fe.

Originally appeared in
The Collector’s Guide to Santa Fe and Taos - Volume 9

Related Pages

Collecting Antique Prints article
Contemporary Lithography article
Conservation Preserves Your Art article
Fine-art Etchings and Engravings article
Handmade Paper article

Ledger Drawings — Then and Now article
Reproduction or Print — What's the Difference? article
What is a Monotype? article
Works of Art on/of Paper article

Collector’s Resources

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Darryl Willison | 505-238-6469
Susan J. Zimmerman rem By Appointment in Corrales | 505-280-4755
Leich Lathrop Gallery rem 323 Romero St NW - Suite 1 | 505-243-3059

Elsewhere in New Mexico

Roswell Museum & Art Center | 575.624.6744
Josie's Framery | 575-257-4156

Santa Fe

Pablo Milan Gallery | 505-820-1285
EVOKE contemporary | 505-995-9902
Arroyo rem | 505-988-1002
The Karen Wray Gallery rem 2101 Trinity Drive Suite B-2 | 505.660.6382
Pippin Contemporary | 505.795.7476
GF Contemporary | 505.983.3707
Robert J. Kelly rem 229 Camino Del Norte | 505-983-3590
Matthews Gallery | 505-992-2882
The Owings Gallery | 505-982-6244
Lori Snable rem 607 Paseo del la Loma | 505-795-1212
Vivo Contemporary rem 725 Canyon Road | 505-982-1320


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