Causes and distribution of stress in canvas paintings

Abstract

Since the manufacturing technique of canvas paintings entails in having various layers of composite materials adhered together, any microclimate fluctuation causes a decrease or increase of stress throughout the whole painting. Each layer experiences a different degree of dimensional change with the alteration of its internal moisture and heat content. Another stress generator is the application of pulling forces supplied by the structural frame. Expansion of stretchers also causes a highly uneven canvas deformation. This is mainly caused by the canvas's fixed points to the stretcher bars and initial canvas attachment to the stretcher frame during the manufacturing technique. The uneven yam movement contributes to a non-homogeneous distribution of stress transfer to subsequent layers-mainly consisting of preparatory and paint layers. Problems related to the conservation-restoration of the painting could arise if the level of stress exceeds the cohesive and adhesive forces of the stratigraphical layers. Cracks, cupping, and flaking of the paint film are amongst the main products of mechanical fatigue. To reduce the rate of such deterioration, it is necessary to investigate the sources of stress instability.