Shrinkage and mechanical properties of drying oil paints

Abstract Understanding how the evolving molecular composition of an oil paint layer on its transition to aged solid film affects dimensional change and mechanical properties is fundamental assessment material durability more broadly risk degradation paintings. Tensile properties—modulus elasticity strain at break—as well as cumulative shrinkage were determined for a selection paints from Mecklenburg’s Paint Reference Collection now after approximately 30 years drying. The found get stiffer brittle with diminishing plastic deformation increasingly elastic behaviour. For some paints, increases in stiffness decreases break dramatic during late stage observations modify current physical model paintings which mismatch response glue-based ground unrestrained wood or canvas support variations relative humidity (RH) has been identified worst-case condition fracturing entire pictorial layer. This study demonstrated that than consequence vulnerable cracking. due relocation and/or evaporation organic medium they dry age was measured. can exceed their lead if it restrained by dimensionally stable substrate. Consequently, long-term drying, cause crack even absence fluctuations RH temperature. An example cracking developed top undamaged historic panel painting made evident X-ray microtomography.