Deterioration of artifacts is a natural process which begins immediately when the objects are fabricated and proceeds throughout their lives. It is natural in the sense that it is the response of materials to reach a state of physical and chemical equilibrium with their immediate environment. Composite objects such as panel paintings are especially prone to damage due to humidity fluctuations. The wooden support swells and contracts with changing humidity. The paint film however does not react to changes in humidity in the same way resulting in cracking and eventual flaking off of the paint layer. Another area of concern is the problem of mould growth. Fungi thrive in damp atmospheres and will form on many organic materials, such as leather, paper, textiles, etc. Stains may develop because of this and in extreme cases, destruction of the object is even possible.
