Whether objects are in a home environment or a gallery setting, in storage or on display, there are many simple steps a collector can take to ensure that the works of art in their care are preserved for generations to come.
A first step is careful consideration of the materials individual items are created with, and the special needs unique to the various media. Panel paintings for example, can be particularly fragile as wood can crack or warp in reaction to temperature and humidity fluctuations. Oil on canvas paintings, each created with an individual application of ground layer and pigment, are also susceptible to environmental damage through cracking and cleavages of the paint layers, or deformations of the canvas support.
Art on paper is susceptible to the acidic elements contained within most commercial paper stock which, over time, can react internally to destabilize the paper. Works of art made using poor quality paper are particularly susceptible to deterioration, but the reaction may be exacerbated by acid migration if the paper is mounted onto acidic backing boards or mats which can cause discoloration and embrittlement. Minute metal shavings, introduced during the paper manufacturing process, can also corrode when exposed to humidity, resulting in dark rust spots known as foxing. Once it has occurred, foxing is often difficult to remove, although it can be minimized through vacuum suction cleaning techniques or careful retouching with appropriate conservation paints. As the metal particulates are inherent to the papers construction, foxing is best prevented through proper framing to conservation standards and the maintenance of climate-controlled storage or display environments.
Even stable materials, including stone, metal or glass, are susceptible to accidental breakage, scratches, cracking, corrosion or reaction to environmental pollutants. Vases and bowls, for instance, should always be picked up and carried by the base rather than the neck or lip, as these can be quite fragile and can break away from the body if placed under stress. Sculptural objects should also be placed on secure and stable display shelves or stands large enough to support their weight, away from high traffic areas.
Two other important considerations for your collection are temperature and humidity. Climatic consistency is critical. Rapid fluctuations can cause items to expand and contract, destabilizing support structures, whereas stable levels can help preserve your collection for generations. Mid-level humidity can prevent mold growth and deter insect infestation, while cooler temperatures can minimize the natural process of aging and deterioration. As a result, most museums try to maintain relative humidity levels at approximately 40%, and temperatures of 68 to 70 degrees Fahrenheit.
To stabilize your environment, use dehumidifiers in humid areas during summer months and humidifiers in dry climates or during winter, when heating vents and fireplaces dry out the air. In air-conditioned environments, careful control and monitoring of humidity levels are particularly important along with regular cleaning and maintenance of filters and heating, ventilating and air conditioning units. A Precision-Hair hygrometer carefully and routinely monitored can provide precise readings. These simple devices can help you easily monitor interior humidity levels on a regular basis. What is most important, however, is to keep the environment stable. While it is tempting to turn air conditioners or heating systems down when you are away from home, this can create daily temperature and humidity fluctuations that can cause long-term damage. A constant temperature is best for your collection, one that is not too warm or too cool, too moist or too dry.
Reducing exposure to sunlight or artificial sources of light is also important. Ultra violet ("UV") radiation causes fading and uneven heating. It can particularly damage paper items such as photographs, watercolors and works with colored inks, as well as textile fibers and dyes. Picture-lights mounted to frames should be avoided as they can create hot spots or burn and tear the surface if they fall or break. In general, the bluer or "cooler" the light, the more UV it contains. Indirect sunlight or recessed or ceiling-mounted lighting is best for displaying artwork. Keeping curtains and shades drawn and turning off lights when a room is not in use are other ways to control light exposure. If your rooms get sun only part of the day, automatic timers can lower window shades as needed. For convenience, UV-filtering film can be installed on widows and lighting elements. As the effects of light exposure are cumulative, rotate artwork in and out of storage every three to six months.
When planning display, location is significant. In general, place items on interior rather than outer perimeter walls, which experience greater climatic variations. If artwork must be installed on exterior walls, rubber spacers on the back of frames can facilitate air circulation and minimize harm. Although tempting, focal points such as fireplaces expose any artwork hung over them to heat, soot and fluctuating humidity levels. Heating and air conditioning vents, which spread dust and environmental particulates, are also detrimental. Artwork should not be hung in bathrooms, below pipes, which can leak or drip condensation, or near any exposed water sources. Artwork in high-traffic areas should be carefully placed to avoid accidental injury and hung high enough to prevent unintended damage from handbags, chair backs or doors.
Quality museum framing using conservation materials is important to the long-term preservation of artwork. Works of art on paper and textiles are particularly susceptible to improper framing, and should only be mounted and backed with acid-free materials such as museum ragboard or blueboard. Ensure that adhesives are archival and reversible. Matting and archival hinging are also important as unmatted items can become permanently adhered to the glazing (i.e., to the glass or plexiglass), particularly in high humidity environments.
Glazed items should offer UV protection to reduce light exposure. While many items can be framed under UV-resistant plexiglass, powdery or loose pigment such as pastels or charcoal should be framed under glass to avoid static build-up that can disturb these materials. UV glass, particularly museum glass or den anti-reflective glass, is another available alternative. A protective dust-seal backing can prevent dirt, dust and insect contamination. Proper hanging hardware attached directly to the frame is an important final step. Always hang items from picture hooks, and check specifications carefully to ensure that weight will be properly distributed.
In general, it is impossible to have too much information when it comes to the care and handling of works of art, so if you have questions, contact a conservator, a framer specializing in preservation framing, or a professional art installer for advice and assistance.