SOURCE: THE BRITISH ASSOCIATION OF PAINTINGS CONSERVATORS-RESTORERS
Care For Your Paintings
When considering the best place to display/store paintings the following should be taken into account.
Temperature
Paintings should be kept in a stable environment, avoiding extreme high and low temperatures. 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. Museums recommend that paintings to be displayed at temperatures between 18 and 24°C.
Relative Humidity
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.
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 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.
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. Tip: Do not use a feather duster or any type of cloth that will catch on to the painting, in case of flaking. Using soft brushes or clothes with even strokes will prevent damage. Being gentle is the key.