PROTECTING ARTWORK FROM ULTRAVIOLET LIGHT
by Laura Stirton Aust, ARTcare
Light is an unavoidable hazard to art materials, especially paper. Light causes weakening and discoloration of paper fibers. It also causes many dyes and pigments to fade or change in color. The damage from light is not reversible. Faded pigments can not be put back and light burn will unevenly stain paper. Therefore decreasing exposure to all light, especially ultraviolet (UV) is a significant concern in protecting artwork. UV is the highest energy and most damaging light and mostly invisible to the human eye. Eliminating UV from light has very little visual effect on artwork. Most museums filter UV from light sources and reduce light exposure by limiting the number of hours art is illuminated. There are also guidelines for museums intended to minimize damage from light. For example, works of art on paper should be stored in darkness with exhibition not to exceed six weeks every two years. These rules obviously are not practical for individuals. But, reducing UV is manageable for anyone who is willing to take the effort necessary to protect art from the hazards of light.
FILMS AND WINDOW COVERINGS
The primary source of ultraviolet radiation is sunlight. Window films and some coverings provide UV filtering without blocking substantial visible light. UV filtering of sunlight will help to safeguard prints, furnishings and textiles while also reducing the heat entering a window.
Clear and tinted window films are maintenance-free and often carry a ten year warranty. Most films have a metallic coating that reflects 50% of solar heat and 98% of ultraviolet radiation. The coating slows heat loss in winter by 15% because it increases the window’s insulation. There are many brands available. Two distributors I have worked with are Solis International (800.220-2525) and Solar Master Corporation (800.257-0448). The internet and Yellow Pages list many others.
Although most films are not detectable, a few have a reflective appearance. Some condominium and apartment regulations disallow those films which from the exterior may give windows a different appearance from those windows without film. If film is not an option, then window coverings, i.e. shades or curtains are an alternative. The disadvantage compared to applied window films is that they reduce UV only while closed and they should be closed even on cloudy days. It is also worth noting that even indirect sunlight contains UV. In fact, north light contains more UV radiation per foot candle (a measurement of brightness) than south light. There are however materials which filter UV without blocking the view. Sol-R-Veil (212.924-7200) makes a translucent fabric roller shade that blocks 98% of UV and is used by many museums and corporations. Solar Screen (718.592-8222) mylar roller shades and sheets (a thicker version of the applied films) are also available.
PROTECTING ARTWORK IN THE FRAME
Glazing is the protective covering used in framing artwork. The two most common glazing materials are glass and plastic. Glass is rigid and not easily scratched. It has no static electric charge. But it is heavy and breakable. Tru Vue Conservation Glass and Denglas are both satisfactory UV filters used for glazing. “Non-glare” or “anti-reflective” glass has an etched surface which scatters light to prevent reflections but does not filter UV.
Plastic is light weight and less breakable than glass. But, it is easily scratched and not as rigid as glass. Plastic also carries a static electric charge which encourages the lifting of loose media found on pencil drawings, mezzotints, and pastels. There are a number of glazing products which filter UV. Acrylite, Lexan, Lucite, Perspex, Picture Saver, and Plexiglas all make plastic glazing with UV filtering properties. Your framer is likely to stock several brands. Most of these products are colorless and will filter UV for the life of the plastic. As the plastic ages it may take on a gray or yellow cast. It is still filtering UV but you may want to replace it if the appearance of your art is affected by this coloration.
FLUORESCENT BULB SLEEVES
Fluorescent light contains less UV than sunlight though the UV output is still significant. Because fluorescent fixtures produce little heat and use very little electricity they often remain illuminated for many hours. Since light damage is cumulative it takes only a few weeks for fluorescent light to damage art. But, if fluorescent light is filtered there is much less danger. Talas (212.219-0770) is one of many distributors of mylar sleeves that cover fluorescent bulbs and control UV emanation without reducing visible light. A sleeve will also prevent shattering of the bulb. These sleeves will filter UV for the life of the product. But, like most plastic as it ages it becomes brittle. So, if the sleeve cracks or chips it should be replaced. If the light seems gray or yellow you may also want to replace the sleeve.
Sometimes I am asked if it is necessary to use all these methods to filter UV. Having seen paper burned by the sun in only a few days I can not over emphasize the dangers of UV. A newspaper left on a window sill for a week provides a graphic example of the damaging effects of sunlight. I believe in using multiple defenses. Window film is the most difficult and expensive undertaking. But, films are the best first step in a preservation strategy and they have benefits beyond protecting artwork. The next most protective approach is UV filtering glazing. An added benefit is that every piece framed with UV filtering glazing is protected no matter where it hangs. Finally, sleeves for fluorescent bulbs are so simple to install and inexpensive it is hard to understand why someone would not employ this cautionary step. Don't wait for light to damage your artwork. Avoid illuminating pieces whenever possible and do all that you can to reduce UV from the sources that light your artworks.
