Softening paint and drip formation in paintings by Jean-Paul Riopelle (1923–2002) : Improving their condition with metal coordinating ions

The authors of this paper have undertaken various technical and chemical studies, mainly direct temperature-resolved mass spectrometry (DTMS), hand-held x-ray fluorescence (XRF) and scanning electron microscopy/energy-dispersive x-ray (SEM/ EDX), on the softening and dripping paint in Composition (1952) by Jean-Paul Riopelle. This has provided an understanding of the chemical difference associated with variations in the condition of the paint. The authors have proposed the theory that a fraction of the oxidised oil binding medium phase separates from the paint due to a lack of anchoring points for the increasing amount of polar fatty acids resulting from the oil oxidation process. In the study, lead (II) acetate in water or ethanol solutions
was introduced into paint samples from soft paint, drip material and the drip material in solution. The chemical reaction of the samples was investigated by polarization microscopy in visual and UV light, Fourier transform infrared spectroscopy (FTIR) and
SEM/EDX. The results show that lead ions react with the acid groups in the binding medium thus fixing the acids as lead carboxylates. The success of this introduction depends on the degree of penetration of the lead ion solution into the paint. Ethanol appears to open the paint structure more effectively than water.