Identification of lipid binders in paintings by gas chromatography - Influence of the pigments

The influence of the presence and the type of pigments in the lipid binding media of paintings were studied by gas chromatography with flame ionizatio n detector. The drying oils were linseed stand oil, poppy oil and sunflower oil, and the pigments studied were cadmium red, cobalt blue, tin white, le ad white, chalk and plaster of Paris, commonly used in paintings. The resul ts indicate that the stearic/palmitic ratio and the presence of pigments ar e quite stable during ageing. However, some differences in the oleic acid/p almitic acid ratio were found, depending on the type of pigment present in the lipid binding media. These variations are related to the drying effect of the pigments. The proposed method has been applied to the identification of drying oils in two samples from baroque paintings in the "Basilica de l a Virgen de los Desamparados" of Valencia, Spain. (C) 2001 Elsevier Science BN. All rights reserved.