The Extraction of Soluble Components from an Oil Paint Film by a Varnish Solution

Abstract

This paper describes an investigation into the effects of a varnish applied to an oil paint film in terms of the extraction of soluble material from the paint film by the varnish solution. A series of oil paint films were coated with varnishes formulated with a range of resins and solvents. The extraction of fatty acids from the paint film into the varnish layer was measured by gas chromatographic analysis of the dried varnish film and of samples of the paint film before and after treatment. The quantities extracted were found to depend not only on the solvent used to apply the varnish but also on the resin component, with varnishes formulated with more polar, oxygenated resins extracting more than those made from nonpolar, hydrocarbon resin. The results are interpreted and discussed in the context of investigations of the effects of free solvents on oil paint films.