Study of the degradation of Cadmium Yellow in historical and historically reconstructed oil paints

This proposal concerns the study of the composition and degradation of Cadmium Yellow (CdY) oil paints in relation to the historical synthesis methods of the pigment. Although the degradation mechanism of CdY paints has been elucidated, it has been demonstrated that not all CdY paints show the same extent of degradation. This fact can be related to the use of different historical synthesis methods, which influence the pigment properties and could induce a different reactivity of the pigment. We propose to characterize through µ-XRF/µ-XANES analysis the chemical speciation and stratigraphic distribution of compounds in artificially aged CdY model paints prepared with pigments synthesized by different historical methods, to provide a quantitative assessment of the degree of degradation in relation with the manufacturing process. The research will complement the study of historical paint samples from original CdY degraded paintings, to compare artificial degradation with real one.