What do art conservators have in common with Stephen King? Both have horror stories galore. Hung directly above a collector’s bathtub, a masterpiece is inundated by clouds of steam. Stored in a dank closet, a 17th-century Dutch painting is ruined by creeping mold. Checked at the airport like a suitcase full of toiletries, a rare oil-on-canvas is impaled by an errant forklift. More common casualties include paintings baked by heating vents, blasted by sunlight, soaked by roof leaks or browned by smoky cocktail parties.  Whether antique or contemporary, acrylic or oil, all paintings face manifold threats. But by studying basic principles of conservation, collectors can do much to protect their valuable artworks.

Humidity

Extremes of humidity and dryness can wreak havoc with paintings. Air saturated with moisture often leads to insidious mold growth that returns again and again. “Mold is actually a permanent condition,” says Heather Becker, CEO of the Chicago Conservation Center Inc. “Once mold has embedded itself in the surface of a painting, it is almost impossible to eliminate.”

The opposite extreme—excessively dry air—can cause paintings to warp and crack, as can rapid fluctuations in humidity. “The canvas or panel actually expands and contracts with the humidity,” explains Mark Bockrath, paintings conservator for Winterthur, Henry Francis du Pont’s country estate in Winterthur, Delaware. “This causes the paint to break and then pop off.”

To prevent such problems, the American Institute for Conservation of Historic and Artistic Works (AIC) urges collectors to invest in climate-control systems that keep artworks at a relative humidity of between 40 and 60 percent. Climate-control systems also help protect against harmful air pollutants. In particular, soot from candles, accidental fires and tobacco smoke can cause acidic, oily layers on a painting’s surface. “Soot damage is reversible if you catch it in time and prevent it from degrading the pigment layer,” Becker notes. “That’s why in the event of fire damage—and also water and mold damage—people should contact a conservator immediately.”

Light and Heat

As with humidity, conservators warn against rapid fluctuations in temperature. Avoid, for example, turning off the air conditioning during the day and on again at night. Even if the room stays an ideal 65 to 75 degrees, artworks can be exposed to ruinous spot heating. Sunlight is the top culprit, but many collectors mistakenly hang paintings above working fireplaces or place them too close to artificial lights. “I once visited someone who had a wonderful collection of American paintings,” Bockrath recalls. “He insisted on lighting them with top-mounted picture lights that generated a lot of heat, and the paintings were all flaking and cracked.”

A dramatic landscape might look even more so in the afternoon sunlight, but those heavenly shafts of gold also contain invisible ultraviolet radiation, which causes varnishes to yellow and pigments to fade. “What’s tricky about ultraviolet is that it’s always present in daylight,” says Pierre Blanc, owner of New Rochelle, New York–based Sunshield Energy Control Systems. “People think sunny days are the only time UV damage occurs, but if it’s rainy or snowy and the blinds are open, UV gets in.” Mindful of this, some collectors occupy darkened mansions reminiscent of Castle Dracula. Blanc’s company sells and installs heat-reducing, UV-blocking window coatings that allow for a less gothic existence.

In cases where artificial lighting is used, collectors should steer clear of high-intensity bulbs, says Naples, Florida– based art dealer Paul DeBruyne, whose DeBruyne Lighting sells a variety of gentle, UV-blocking systems. DeBruyne recently visited an art gallery that was virtually toasting canvases worth seven figures. He says many collectors and dealers are woefully unaware of the effects of light damage. “Last year I saw an 11-color Renoir lithograph worth six figures that was terribly faded,” he says. “It’s tragic.” (For more on properly lighting paintings, see Art & Antiques, June 2003, page 38.)

Improper Hanging

Some problems are relatively easy to avoid. “Frankly, I get a number of paintings that have damage to the frame and canvas from having fallen off the wall,” says New York City–based conservator Gloria Signorelli, who specializes in antique European paintings. A fine-art framer or professional art- handler should be hired to hang works of significant value, Signorelli notes. Collectors should also periodically check the wall and mounts behind each of their paintings. In older estates, Bockrath says, failure to do this can result in paintings that have hung for generations suddenly crashing to the floor—or onto, say, a Chippendale chair.

Improper Storage

Ideally, paintings should be stored in climate-controlled, art-storage warehouses. Never cover stored paintings in Bubble Wrap or brown paper without first putting down a protective layer of Glassine, Becker says. “Sometimes the brown paper can stick to the surface due to a tacky varnish,” she notes. “Bubble Wrap, if put face-in, can actually make an imprint on the painting.” It’s also a good idea to interleaf stacked paintings with strong cardboard or foam-core board. “Otherwise you could have one painting stick to another,” Becker says, “or a stretcher bar from one painting could cause a crease in another.” Attaching cardboard or foam-core board over the back of a painting adds protection against puncture damage and leaks, adds Bockrath.

Cleaning

According to AIC, collectors should never clean a painting themselves. Household cleaning products can do serious damage, and even feather dusters can scratch paintings. It may be acceptable to dust a painting using a soft sable brush, but only if there are no loose paint chips.

Working with Conservators

Collectors should regularly inspect their paintings and track any changes in condition. Conservation basics also can help in evaluating potential acquisitions. Has a work been over-cleaned or its stretcher over-keyed? Has it been suspiciously re-canvassed or its pigments altered? Knowledgeable collectors often can answer such questions for themselves. In other cases, they rely on professional advice. Becker notes that conservators’ fees should be based on time and materials, not on the artwork’s value. And conservators should never double as appraisers—the unscrupulous could give inflated appraisals, thereby persuading clients to have their artworks conserved. AIC members pledge to follow a code of ethics. The Washington, D.C.–based organization offers free brochures listing members by region and gives tips on choosing a conservator.

For more information
The American Institute for Conservation of Historic and Artistic Works, Washington, D.C. (202) 452-9545. 
Chicago Conservation Center Inc., Chicago. (312) 944-5401.
DeBruyne Lighting, Naples, Fla. (800) 967-1268.
Signorelli Studio, New York City. (212) 288-4683.
Sunshield Energy Control Systems, New Rochelle, New York. (914) 633-5853.
The Winterthur Guide to Caring for Your Collection, edited by Gregory J. Landrey (University Press of New England, 2000).