The paper discusses the mechanical properties of oil paintings on fabric support. The modulus, breaking strength and stress development of the isolated layers, fabric, glue and paint film were measured under varying environmental conditions. The results show that the glue and paint layers contribute far more to the structural support of a painting than the fabric does. A composite structure of these results compares very closely with measurements done on a 70-yearold painting. The results also indicate how the cracking of the paint film is generated. This research is suggestive of various means by which further deterioration of paintings on fabric supports can be slowed. -- AATA