Caring for Works of Art on Paper


By Esperanza Romero

The Basics
Although works of art on paper such as prints, drawings, and watercolors are inherently fragile, they can be easily and effectively protected from damage and deterioration. Preservation measures include:

  • proper storage and handling, including framing
  • protection from light
  • protection from unsafe temperature and relative humidity conditions
  • protection from pollutants and airborne particulates.

Proper Storage and Handling
Works of art on paper should be touched as little as possible. Be sure that your hands are very clean, or wear white cotton gloves. Better yet, mat, frame, or store the works in a manner that permits viewing and transporting without direct handling.

Because paper is damaged by prolonged contact with acidic surroundings, the choice of storage and mounting materials is crucial. Mats, folders, and mounting adhesives must be chemically stable, nonstaining, and permanent but reversible. Although framers are more knowledgeable today, some are still unaware of the importance of using preservation-quality materials. It is essential to find one who does. A paper conservator or a major museum can refer you to such a framer. If your works on paper were framed commercially before 1980, poor-quality mounting materials may have been used. One common sign of poor mat board is browning of the cut edge of the window opening. If you are unsure of how to identify the material in your framed artwork, consult a paper conservator.

The Essentials of Proper Framing

  • a mat window and backboard made of 100% ragboard or the lignin-free, alkaline-buffered matboard especially for preservation purposes
  • attachment of the artwork to the mat or mount by hinging with high-quality Japanese paper and a permanent, nonstaining, reversible adhesive. Homemade starch paste is the choice of conservators. Avoid commercial tapes, including those advertised as archival. If you want to try to do your own matting, a paper conservator can advise you about sources of supplies.
  • protective glazing, either glass or rigid acrylic. The artwork must not be in direct contact with the glazing material. Ultraviolet filtering products, available in glass as well as plastic, are recommended to protect against the most destructive component of light. Note that acrylics carry a static charge and must not be used with pastels, charcoal, or other powdery or flaking medium.
  • an additional protective layer of sturdy, lignin-free cardboard at the back of the frame. The frame should also be well sealed to discourage entry of air.

Unframed works of art must have individual protective enclosures. Although matting is preferred, sturdy individual folders are an acceptable alternative. Like matboard, these folders must be made of lignin-free, buffered stock that is rigid enough to provide adequate support. To protect the edges of the artwork, folders should be somewhat larger than their contents. Objects in folders or mats should be stored flat in lignin-free boxes such as heavy-walled Solander boxes, the traditional choice of museums. Oversized works of art are best kept in the drawers of flat files (map cases). These files should be made of metal rather than wood since wood gives off acidic gases. Wood files can be used if the interior of the drawers is sealed with a water-based polyurethane coating and lined with a suitable barrier material such as lignin-free board or 5-mil polyester film (Mylar). If you purchase storage drawer units, anodized aluminum or powder-coated steel are recommended.


Javier Carmona

Protection from Light

Light causes fading of certain media, especially watercolor, pastels, and many drawing inks. It can also darken or embrittle paper. Light damage is cumulative and irreversible. Because all light will cause damage, conservators recommend that no work on paper be permanently displayed.

The best display conditions are those with low light levels and no daylight. Block windows with shades, blinds, or curtains. Light sources containing ultraviolet (UV) rays are especially harmful. UV is found in all daylight, most abundantly in sunlight, and in the emissions of certain artificial lights, such as most fluorescent and metal halogen lamps. Ordinary household bulbs (incandescent or tungsten lights) contain negligible UV and are therefore recommended. These bulbs give off heat, however, and should not be placed near the artwork.

Special filters are available to screen out UV radiation. Inexpensive plastic sleeves can be purchased for fluorescent tubes. Windows or cases can be covered with stick-on UV-absorbing films, or rigid sheets of UV-filtering plastic or glass can be used in frames or windows.

Protection from Extreme Temperature and Relative Humidity (RH) Conditions
  
Because warm or moist conditions accelerate deterioration, temperature and relative humidity (RH) should not exceed 20C and 60%, respectively. High temperature and RH also encourage mold growth and insect activity. Very low RH, below 25%, is believed to be less damaging but may cause paper to become brittle.

Temperature and RH should remain constant. Climatic fluctuations cause expansion and contraction, which can lead to structural damage in paper, weaken the attachment of media, and cause distortions such as rippling of paper. Frames and storage enclosures may provide some degree of protection against daily fluctuations but will not protect paper from long-term or seasonal changes.

Temperature can usually be controlled by heating and air conditioning, but more expensive equipment may be necessary to keep the RH constant all year. Lacking such equipment, some control can be maintained by using portable dehumidifiers in summer and by lowering the heat in winter.

During periods of high humidity, use fans to circulate air and help discourage mold growth. Above all, do not store works of art in basements or attics. Do not hang them in bathrooms or over heat sources. Unless the building has excellent climate controls, do not subject art on paper to seaside locations or other damp areas.


Teiko Mori

Protection from Gaseous Pollution & Airborne Particles

Dust and soot will soil delicate, porous paper surfaces and are difficult to remove safely. Ubiquitous pollutants from industrial gases, auto emissions, and heating compounds are readily absorbed into paper, where they form harmful chemicals that discolor or embrittle. In addition, sources of internal air pollution, such as copying machines, new construction materials, paint fumes, new carpets, janitorial supplies, and emissions from wooden cabinets, can attack paper.

Controlling air quality is often difficult. Probably the most practical way to protect art on paper is to enclose each object in protective housing made with appropriate materials.

When Disaster Strikes
 
Although hurricanes and earthquakes may be rare, water accidents are common. Even a small amount of water from a leaky roof or pipes can do significant damage to a paper collection. If objects get wet, call a paper conservator or a museum immediately. It is important to dry paper right away before mold sets in. Wet objects in frames with glazing must be removed from their frames. If you are hesitant to handle the damp paper, expose the object by removing the backing from the frame. If the collection is too large to dry right away, freezing may be necessary. Speak with a conservator first.


Paco Aguilar

When to Call a Conservator

Treatment of art on paper must be done by qualified conservators specializing in paper, not by those who claim to treat all types of objects. To find a conservator, contact the AIC office.

Some conditions need immediate attention, while others can wait. Wet or moldy materials or those with actively flaking media have high priority. So do brittle or fragile papers in danger of splitting or tearing. Because they can stain within months, recently applied self-stick tapes or labels should be removed immediately. Objects stuck onto brittle or acidic cardboard may not require emergency action, but they should be separated from their mounts as soon as possible. When in doubt about the urgency of treatment, show the object to a paper conservator.


Information provided by: http://www.spanishprintmakers.com