An important element in the long term survival of a museum collection is the environment they are kept in both for storage and display.
Sensors are set up in the galleries and stores to monitor the relative humidity and temperature. It is important for the objects that the moisture in the air is kept at a constant level to prevent expansion and contraction of the materials. A high moisture level will increase levels of corrosion and cause mould growth whilst low levels will cause organic materials to become brittle and crack.
The UV content of light damages objects. It not only fades colours but can destroy the structure of materials such as textiles, leather, paper and lacquer. Maintaining low light levels helps preserve the collection.
Air pollution can be a problem from sources such as car exhaust fumes, power stations, industry and even humans! We use filters to remove both gases and particles.
Insects cause damage to organic materials. New objects coming into the museum are held in a quarantine zone until they are checked and if necessary treated for insect infestations. Only if they are clear will they be allowed into contact with the rest of the collection. To monitor the collection, traps are placed round the museum to alert us if a problem arises.
Everything that is used to make up a showcase may give off gases that will react with the objects to cause deterioration. We can test all the materials such as paint, fabric, backboards and floorboards. We take a sample of the material and place it inside a sealed jar with coupons of copper, silver and lead.
The jar has a small amount of water in the base and it is heated in an oven for a month to accelerate the ageing of the material. By looking at how the metal coupons change we can determine the extent of damage the material may cause. Comparing the coupons to the control shows just how much damage can be caused by the material being tested.