The extraction of soluble components from an oil paint film by a varnish solution

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 t he paint film by the varnish solution. A series of oil paint films were coa ted with varnishes formulated with a range of resins and solvents. The extr action of fatty acids from the paint film into the varnish layer was measur ed by gas chromatographic analysis of the dried varnish film and of samples of the paint film before and after treatment. The quantities extracted wer e found to depend not only on the solvent used to apply the varnish but als o on the resin component, with varnishes formulated with more polar, oxygen ated resins extracting more than those made from nonpolar, hydrocarbon resi n. The results are interpreted and discussed in the context of investigatio ns of the effects of free solvents on oil paint films.