Saving Old Master Prints

The months leading up to Master Drawings New York (January 21-28) are busy ones for Center Art Studio in midtown Manhattan. One afternoon, Lansing Moore— who is about to celebrate his thirtieth year as proprietor of the studio, which was founded in 1919—took a break to describe the process of conserving artworks on paper.

“The aim is to retain the character of the old paper while improving its strength and flexibility, without making the artwork look like new,” explained Moore, who is a passionate art collector, dealer, conservator and (with wife Iliana) blogger. “We’re extremely conservative—we don’t add things unless we have to.” In other words, less can be more.

Old works on paper, especially those that haven’t been in a frame, often benefit from dry-cleaning. Yes, dry-cleaning.

No chemicals are used. Rather, as the term suggests, the surface of the paper is cleaned without using any moisture – a kind of gentle erasure. Until the 1950s, when paper conservation was a new field, dry-cleaning was often done with freshly baked bread, balled up and rubbed lightly over the surface of the paper to remove dirt. Today, Moore and most paper conservators use pure latex sponges, which gently remove surface soil and leave no crumbs behind. Dry-cleaning can only be done in areas where the medium will not be disturbed, and it is not appropriate for works in graphite, chalk or pastels. Insect deposits can also be eliminated at this time; old pressure-sensitive tapes and adhesives are removed with Q-tips and solvent.

In his studio Lansing Moore pauses while removing old hinges from the eighteenth-century mount of a self-portrait drawing by Annibale Carracci.

At this point Moore decides whether the print needs washing, to remove acids and other impurities trapped among the fibers. As he explains, “It’s important to dry clean before washing or the dirt might be driven even deeper into the paper fibers and never come out.” If washing is called for, Moore tests inks and colors to be certain that they will remain stable in water. He then carefully presses or rolls dampened Q-tips in inconspicuous areas of the print. Paper, in fact, is strong enough to withstand washing if properly supported by a sheet of polyester or other such material. Without adequate support, wet paper will almost certainly tear.

After dry-cleaning and washing the artwork, Moore flattens it between pure cotton blotters, with a protective layer of polyester or tissue to prevent the paper from adhering to the blotter. By changing the blotters periodically, the paper can gradually dry, clean and flat.

BEFORE: The print had been framed with “faux grasscloth” mat. Note the discolored amber bevel of the mat—a sure sign of acid damage.

AFTER: After successfully cleaning the print, Moore mounted it in a thick, eight-ply cotton rag matt.

If stains or general discoloration are still evident, Moore must decide just how far to take his treatment. Old prints and drawings, he stresses, should “retain a sense of their history and age.” He might spot-treat especially distracting stains, but otherwise he prefers to “leave the paper exhibiting its lovely warm, aged appearance.”

When there are tears or holes in the paper, he will work from the back, applying mends of thin, strong Japanese or Western paper with starch paste, carefully matching the weight of the mending tissue to the weight of the artwork paper. Larger fills that will be evident from the front are tinted to harmonize with the paper. When the artwork has been fully conserved and ready to be put into a frame, Moore applies Japanese tissue hinges to the back of the artwork and attaches these to an acid-free mat board backing.

Moore is looking forward to Old Masters New York. With 23 of the best dealers from around the world, he says, it’s a must for anyone interested in prints and drawings: “These exhibits, timed to coincide with the sales of Old Masters at Sotheby’s and Christie’s, offer a great opportunity for everyone to see hundreds of works not normally on view.”

BEFORE: This oil sketch on paper by Johan Zoffany (1733-1810) had a thin layer of varnish, which had yellowed considerably. There was also some lifting of the paper, which had been glued down onto artist’s board.

AFTER: Moore removed the varnish using a mild solvent and cotton swabs. Then, using a ph-neutral polyvinyl acetate adhesive, he secured loose areas. Finally he replaced the varnish with a thin coat of matte Soluvar varnish.

Moore notes that Old Master prints and drawings were generally executed on good quality paper made from pure cotton or linen rags. Despite this, he explains, “it is still necessary to store and display works of art on paper properly if you don’t want to compromise them.”

Moore offers a few rules of the road:

• As soon as you buy (or inherit) a work, “look under the hood.” Open up the frame and look for trouble signs (see box). If you ignore the problems, the piece will change in color in a year. “Decay,” he warns, “is a fast thing.”

• Works of art need to be kept out of direct sunlight and should not be subjected to high temperatures as both will degrade the paper and cause it to darken. Hand-colored media can fade or shift in color when exposed to excesses of light and/or heat.

• Equally damaging to art on paper is exposure to air and fluctuating humidity. Paper tends to absorb acids in the air, causing the fibers to weaken. Disfiguring rust-colored spots known as “foxing” may appear. The unsightly blotches can be very difficult or impossible to remove.

• Good framing is essential to safeguard valuable works of art on paper; it can be a first line of defense against damage and degradation of the paper. While wood is a traditional framing material, it must not come in direct contact with the artwork itself since wood is inherently acidic. Too often, distinct images of knotholes from wooden backings are unwittingly transferred directly to works of art. A museum-quality, acid-free window mat keeps the original artwork away from the glazing.

• Moore underscores the importance of using UV-filtering glazing (either glass or PlexiGlass) as an effective method of cutting down light damage.

• There’s another reason for reframing Old Masters: “When we take off a frame, things are often revealed: hidden documentation, inscriptions, provenance and other historic material.”

• Acidic materials: mats, backings and frames cause darkening or discoloration and general weakening of paper.

• Exposure to sunlight, water damage or excessive humidity can cause fading of inks and colors, darkening and cockling of paper, foxing and mold growth. Fluctuations in temperature and humidity are especially harmful to art on paper.

• Tapes and adhesives, often not apparent from the front of the print, can degrade and weaken paper and cause areas of translucency.
• Artwork pressed directly against glazing can become adhered, causing damage when removed.

What acid mats can do: Moore’s clients had owned this M.C. Escher wood block print Sun and Moon since the artist made it in 1948.

Susan B. Martin is a book and paper conservator with over 25 years of experience. Her studio, Archival Conservation, is located in Manhattan.