Paper Conservation

Paper conservators in library and archive settings specialize in the treatment of works on paper including prints, drawings, watercolors, hand-written and printed documents, pamphlets, maps, and posters.

Paper conservators manage many issues associated with the natural aging of paper, media, damage, and “inherent vice” – a term used when the materials the artist or maker used are innately problematic, such as wood pulp paper with alum-rosin sizing or a document written in iron gall ink.

Collection objects are thoroughly tested, and treatment plans are reviewed with curators before any treatment is performed. Conservators use only high-quality materials that meet the standards of long-term stability. All treatments are documented photographically and with written reports.

In 2018, The University of Kansas was awarded a four-year, $300,000 grant from the Andrew W. Mellon Foundation aimed at bridging the collections care efforts of KU Libraries and the Spencer Museum of Art. Facilitating this collaboration is a jointly-appointed paper conservator who will help to conserve the fine art paper-based materials in both institution’s collections, and share these activities with the KU community.

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A sampling of different Japanese paper mending strips.

A sampling of different Japanese paper mending strips.

The primary goal of tear repair is to restore the structural integrity of the object. Tears leave the object vulnerable to further damage and prevent safe handling and display. Tear repair is usually completed using a piece of Japanese paper placed over the tear using adhesives made in the conservation lab.  Handmade Japanese paper is the preferred material for mending due to its long fiber length, high-quality materials, and visually sympathetic nature. Ideally, the mend should be barely visible to the unaided eye after completion and not cover important information or image areas. Japanese paper uses three fiber types: kozo, gampi, and mitsumata.

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A document lined (reinforced) with two sheets of Japanese paper.

A document lined (reinforced) with two sheets of Japanese paper.

Sometimes whole parts of the object might be missing. “Filling” this loss with new paper aims to restore aesthetic unity, structural integrity, or both. Fills are created by selecting a paper with similar color, weight, opacity, and surface texture. Other times, the loss is filled with wet pulp to “re-create” a portion of the sheet.

Repairing a tear or filling a loss demands that the conservator consider a variety of factors. What is the historical, informational, and/or aesthetic importance? How will the object be handled and used? How will the object be stored?

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A collection of pre-cast paper pulp to be carved and inserted for losses.

A collection of pre-cast paper pulp to be carved and inserted for losses.

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A pulp fill applied to the upper left corner. The top edge is trimmed to match.

A pulp fill applied to the upper left corner. The top edge is trimmed to match.

The pulp is applied while the document is wet and dried together. After drying the fill is trimmed to match.

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A sheet of Gellan gum.

A sheet of Gellan gum.

Rigid polysaccharide gels are used by paper conservators to remove attachments, lining, and adhesives, locally reduce stains, wash objects, measure surface pH and conductivity, and deliver enzymes. Agarose and Gellan gum are the two gels most commonly used in paper conservation. Agarose is obtained from the cell walls of some species of red algae or seaweed. Gellan gum is obtained by fermentation of plants of lily pad varieties. When prepared, both gels form a rigid, clear, sheet that can be cut and shaped for various applications.

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Local stain reduction using Gellan gum.

Local stain reduction using Gellan gum.

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Washing a print using Gellan gum.

Washing a print using Gellan gum.

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Washing test samples.

Washing test samples.

Testing is conducted on non-collection materials to improve treatment techniques. Here, various types of washing techniques were tested on a sheet of 20th century newsprint and a 19th century document to understand washing efficacy. In some cases, it is advisable to wash the entire object, often when it is severely discolored or deteriorating. Preliminary tests are conducted to ensure that the paper and all media can be safely washed and the appropriate solution is selected. One of the primary goals of washing is to remove acidic products from the paper, but not all papers require deacidification. Many historic handmade papers are well-preserved because they contain gelatin sizing, and calcium and magnesium bicarbonate, the latter two introduced into the paper during the processing of the fibers.

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Cosmetic Work and Inpainting.

Cosmetic Work and Inpainting.

“Inpainting,” as opposed to “overpainting,” refers to a technique used in art conservation where media is only applied to an area of the image where color is missing. Inpainting is typically conducted using high magnification to prevent applying media over original material (i.e. overpainting). An isolating layer is applied to the area of loss before the media is applied so that it may be removed in the future. This is a technique typically practiced more frequently on fine art materials, and more often on inserts that help complete an image, rather than on the actual object. Only occasionally is it completed on a damaged portion (such as a scratch or abrasion), and is not carried out on archival materials.