Paintings are susceptible to damage if handled, stored or displayed incorrectly. In an ideal museum setting, paintings are displayed and stored in stable environmental conditions. The lighting, temperature and relative humidity is tightly controlled and maintained at levels thought to be best for the long-term preservation of paintings. Although such control over the environment is not always possible in domestic or private settings, by following a few key guidelines and taking simple precautions you can help preservation of your collection for the future. The information below offers a general guideline.
Regularly inspecting your paintings is key to ensuring that they remain in good condition, for guidance on what to look out for see When to contact a Conservator.
When considering the best place to display or store your paintings the following factors should be taken into account:
- Temperature: paintings should be kept in as stable an environment as possible, avoiding extreme high and low temperatures. Rapid temperature fluctuations pose the greatest danger to the paintings. Lighting which emits heat (infrared radiation) should be kept at a safe distance and paintings should not be hung above working fireplaces, radiators, boilers, outside or on external walls. Acrylic paintings and paintings on wooden supports should be displayed and stored with particular attention to temperature. Panel paintings may crack and split if the wood becomes very dry, and acrylic paintings may become tacky at high temperatures and brittle at low temperatures. Museums recommend that paintings should be displayed at temperatures between 18 and 24°C.
- Relative Humidity (RH): paintings should be kept in an environment in which the RH is as stable as possible. Sudden fluctuations in RH are thought to cause the most damage, and may cause cracks or splits in wooden panels, dirt to be imbibed in soft paint layers and the deformation of canvas supports. Conditions of prolonged high humidity (over 70%) may lead to mould growth, and direct contact with water can cause serious damage to varnish, paint, ground layers and supports. Relatively inexpensive data loggers can be purchased for easy monitoring of RH and temperature. As a guide, museums recommend that RH be maintained between 40 and 60% with no more than 10% variance in any 24 hour period.
- Light: exposure to direct and ambient light can cause damage to paintings, such as fading of certain pigments or yellowing/darkening of the oil medium. Paintings should always be keep out of direct sunlight as ultraviolet radiation (UV) is particularly damaging. Where paintings are lit by ambient daylight, this will also contain some UV radiation and should ideally be filtered to remove the UV component. The simplest way to do this is to fit blinds to windows or to fit solar control film to windows and skylights. Artificial lighting can be controlled by using lower wattage bulbs, increasing the distance between the light and the painting, and replacing unfiltered fluorescent lighting with low UV lighting, such as LED. The museum standard for the display of paintings is 200 lux; however, if your painting contains light sensitive materials, such as fugitive pigments, paper or exposed canvas, it should be assessed individually as the exposure recommendations may be much lower. Light damage is irreversible and cumulative; therefore, if a painting is sensitive it is worth considering limiting both the intensity of its illumination and the time for which it is exposed.
- Dirt and Dust: the accumulation of surface dirt on paintings can be reduced by hanging them away from air flows such as open windows and known dusty areas, for example where pets are kept. Regular cleaning of the areas around a painting can also help to reduce the deposition of surface dirt on the painting itself. It is always advisable to wear cotton or nitrile gloves when handling paintings as the natural oils on your hands can leave fingerprints which attract dust and dirt onto the paint surface. If you notice a considerable build-up of surface dirt on your painting please seek professional advice rather than trying to remove it yourself as the paint surface risks becoming scratched or buffed, and areas of flaking or lifting paint could potentially be dislodged. The best method of long term protection from both dust and handling marks is to glaze your paintings.
Framing, Glazing and Backboards
Glazing paintings can act as a safeguard against potential physical damage, dust build-up and ultraviolet (UV) light (where a UV filtering material is used). Non-reflective laminated glass or Perspex are now readily available and can be fitted by a framer or conservator. There should be ample distance between the paint surface and the glass. Fitting a backboard can also be considered to protect the reverse of the painting from punctures, knocks and deposition of dirt. A backboard also reduces the vibration of paintings on canvas supports and can help reduce the formation of cracks over time.
The best way to protect your painting when it is moved will vary greatly depending on the materials from which it is made, where it is going, how it will get there and who will be handling it. Before making a decision about wrapping, storing or transporting your painting it is recommended that you seek professional advice. Poor practice, or the wrong choice of wrapping materials, may actively damage the painting. We would strongly advise consulting a conservator if the surface is soft, sticky, flaking, infested with insects or mould, or includes loose or sculptural components. Modern, contemporary and acrylic paintings are often particularly vulnerable surfaces and may be permanently damaged by contact with materials such as bubble wrap.
Paintings are often at high risk when being moved. Their surfaces are susceptible to scratches, scuffs, handling marks, tears and cracks. If a conservator or professional art handler is not able to move the painting, to reduce the risk of damage one can:
- Ensure adequate help is at hand
- Ensure that the painting is secure in its frame
- Plan the movement of the painting, including a safe pathway and resting place at destination, before lifting the work
- Remove all jewellery and loose items to reduce the risk of scratching the surface
- Wear cotton or nitrile gloves as dirt and grease from hands can cause irreversible damage to the paint surfaces and gilded frames
- Ensure that you do not exert pressure on the front or the reverse of the canvas whilst holding the painting. A sharp impact from the front or the back of a canvas painting may lead to the formation of concentric networks of spider craquelure in years to come.