Conserving a Panel Painting
There are many factors that affect the condition and survival of a panel painting. If the wood used for the panel support was carefully chosen and the surface properly prepared, this gave it a better chance of survival over time. Likewise, sound painting technique and the use of high quality materials can give similar benefits. However, wood is also a moisture absorbing material that will change shape in response to different environmental conditions (dryness or damp). It is also subject to insect or fungal attack (woodworm, and mould).
The movement of the wood support often causes cracks to appear in the paint and ground following the grain of the wood. These cracks are quite fine, usually visible to the naked eye and often stable. However, if there is too much movement in the support, areas of the paint and ground layers can eventually detach and flake off, resulting in localised losses.
Applying paint too thickly or adding other layers such as varnish in between paint layers can cause other surface problems in the paint, such as localised contraction (or shrinkage) cracking.
Conservation of a panel may involve resolving a variety of structural problems with the wood support, re-attaching lifting or flaking paint and removing discoloured layers of varnish and any overpaint. In order to prevent problems re-occurring, it is important to keep the panel in very stable environmental conditions providing both even temperature and humidity.