The cleaning of paintings: effects of organic solvents on oil paint films

Abstract

The paper is a review of technical studies of the effects of solvents on oil paints in the context of the removal of varnish from paintings. After an introduction describing the historical background to technical studies of cleaning, the various effects of solvents on oil paints are discussed: swelling and softening of the paint binder (which can contribute to the vulnerability of paints to pigment loss during cleaning); solvent diffusion and retention; and leaching (i.e.the extraction of soluble organic compounds from the paint). The paper closes with a discussion of methodological issues in cleaning studies, particularly the relationship between studies on 'model' reference paint films and realistic, 'clinical' studies of actual cleaning operations, considering also the related issue of the ageing of oil paints.