Paint layers on a stretched canvas or solid support present complicated behavior and failure patterns. The article discusses the detrimental effects of environmental changes on the materials involved. The authors report on extensive biaxial tests on dozens of painting samples under variable stress, strain, relative humidity, and temperature. Results indicate that some of the effects of stress can be prevented by firm adhesion to a rigid substrate as compared with the effects when the substrate is more flexible than the surface it supports. Artificial controls such as thermostats or humidistats, however, can compound the problem if the frequency of the cycles is increased.