CONSERVING WORKS OF ART ON CANVAS
by Joelle Steele
Art on canvas, whether oil or acrylic paint, pastel, or mixed media or collage, is a complex combination of many materials, including primers, paints, varnishes, glues, canvas, and wood. All of these sensitive items can be easily damaged by people, including the artist, and by environmental factors. If you want your own art on canvas or the paintings you collect to survive intact for generations to come, you can learn to recognize damage and prevent it by properly conserving and displaying your paintings.
TYPES OF DAMAGE
The following are the most common types of damage to works of art on canvas:
Mold and Mildew. Various kinds of molds can damage paintings that are stored in cool and humid conditions. These fungi can attack the canvas, the stretchers, and the frames.
Insects. There are several pests that can easily destroy a painting. Among them are Woodworms (Anobium punctatum), Silverfish (Ctenolepisma longicaudata or Lepisma saccharina), and Carpet beetle larvae (Attagenus unicolor or Anthrenus verbasci). These pests can eat the canvas itself as well as some of the glues and varnishes.
Media. No two kinds of paint are the same, and some may be mixed with additives that are unstable. Also, no two artists apply paint to canvas or wood panels in the same way. As a result, a painting may fade or discolor, or may exhibit areas of cracked or flaking paint, or missing paint. The varnish may also turn yellow or brown, usually due to continued exposure to light. Glues or adhesives used in the artistic process can also deteriorate over time. Artists should always be aware of the role that their selected materials play in establishing the longevity of their work, as most damage to works on canvas must be addressed by a professional conservator.
Manmade. Canvas can be torn, spilt, or punctured, and it may sag or bulge in places due to careless handling, framing, display, and/or storage. The wooden stretchers can crack or break, and wood panels holding a painting can split, crack, or warp. Paint can be scuffed or scratched, and a painting can become dirty and dusty — and dirt can be very acid, which can causes the canvas and wood to become brittle. Atmospheric pollutants, including cigarette smoke, can alter any organic pigments used when they chemically react with them.
Humidity and Temperature. Do not hang your art on the inside of an outer wall where the cooler wall temperature can create an environment conducive to the growth of mildew and mold within the frame. At the same time, don't hang it near heating vents, fireplaces, or harsh lighting that will make the room too dry and warm. You don't want too much humidity either, so keep your paintings away from water sources found in kitchens, bathrooms, hot tubs, and swimming pools. Changes in the relative humidity and temperature of a room can cause damage as those changes cause the canvas to repeatedly expand and contract. Over time, the paint will likely crack and detach or peel away from the canvas, and the canvas itself may also start to tear or crack. In addition, the wood stretchers and any wood frames can begin to split apart. Ideally, you want the humidity in a room to around 50-60%, and the temperature to be about 64°-68°F. Since this is not always ideal for human comfort, it can be a challenge to prevent this type of damage. But, if a room is reasonably comfortable for a human being, it will probably be suitable for most works of art on canvas. So at least try to maintain the temperature and humidity in the same range at all times, and avoid extreme highs or lows that occur when you turn off the heat at night or while you're away and then crank it up full blast to take the chill off the room when you return.
Light. Keep all artwork out of directly sunlight and avoid using spotlights on the art. If you must light your art, use minimal lighting with UV filtering that is on only while viewing, or use LED lighting at low wattage. Too much light can fade some paints and also the paper used in collages. It is also likely to cause the varnish to get darker and to turn yellow or brown in appearance. It does not take a lot of exposure to light for this to happen.
In general, it is best to not try to restore paintings yourself unless you are a trained art conservator. The cleaning process alone is one that should never be undertaken by an amateur, even a careful one. If you make the slightest mistake, you could end up destroying a painting beyond repair. Even a professional conservator cannot bring back faded pigments to their original brilliance, so it is important to prevent damage in the first place.
As much as possible, do not handle the work of art unless you are in the process of framing it, and then hold it carefully by the edges. Wear gloves when possible to prevent finger prints and the transfer of moisture and oils from your skin onto the painted surface. In particular, do not touch the surface of pastel or not-fully-cured paints or varnishes, as they can be easily smudged and damaged.
Frames should always be deep enough (have a deep enough rebate) to accommodate the art that they hold. Do not put your art on canvas under glass or Plexiglas. Whatever type of hardware you use to hang your framed art should be strong enough to hold the weight of the frame and its contents. Don't hang paintings too close to doorways or in narrow hallways where people can bump into them and possibly even cause them to fall from the wall. When you attach the hanging fittings to the frame, be sure they are fixed to the sides of the frame and not to the top of it. Use sturdy picture wire and run it double strength.
Dust your works on canvas very carefully with a soft natural bristle brush. Make sure that the painting does not have any flaking paint on it before you dust, as that flaking should be repaired first.
Prevent damage to your works of art on canvas by properly handling and framing them, and you will be ensuring the preservation of both the beauty and the value of your art investment.
This article last updated: 02/21/2014.