Different Shades of Cadmium Soaps in Light Aged Modern Oil Mock-Up Paints: First Multi-Analytical Investigation

Metal soaps in oil paints represent a huge topic of research in heritage science involving many different institutions worldwide, which mainly focus on lead- and zinc-based paints. This work documents and investigates for the first time by using a multi-analytical approach, the formation of cadmium soaps in light-aged modern oil mock-up paints made of a mixture of linseed oil as a binder with cadmium red PR108 (CdS, xCdSe) and cadmium yellow PY37 (CdS, ZnS) in known concentrations. The materials selected and the investigations performed on the metal soaps formed on them started as continuation of the Bilateral Research Project carried out from 2016 to 2018 - between the Institute of Science and Technology in Art at the Academy of Fine Arts, Vienna, Austria, and the Light and Colour Science Research Laboratory of the University of Pannonia, Veszprém, Hungary. The first clear evidence of the formation of metal soaps in such materials was documented in 2021. This work is an ongoing research study, also in collaboration with the ALMA Laboratory, Institute of Inorganic Chemistry of the Czech Academy of Sciences, Academy of Fine Arts in Prague, and other important institutions.