Art restorers who have been studying the factors that cause Renaissance oil paintings to deteriorate physically when subject to climatic changes have found that the oil paint used in these paintings actually adjusts to these changes well. The restorers ttherefore hypothesize that it is a layer of material called gesso, which is under the paint, that causes the deterioration.
Renaissance oil paintings are often painted on wooden panels, which swell when humidity increases and contract when it declines most strongly supports the restorers' hypothesis.