Elucidation of pigment degradation processes

The degradation of pigments does not only affect the colour and appearance of well-known paintings, it often entails the flaking or powdering of painting layers as well.  As these alteration phenomena endanger the preservation of key works of art, our group aims to unravell the chemical processes that lie behind the degradation of a number of pigments that were frequently used and are known to become unstable within time. A better understanding of these often complex chemical pathways is an important first step in the setup of effective measures that delay or stop these pigment defects.  We recently focussed on four types of pigment:

These phenomena are studied in various ways: (a) by analysing minute samples extracted from affected, historical paintings (Van Gogh, Rubens, etc.), (b) by characterizing the progression of degradation fronts in mock-up samples that are prepared in the lab and artificially aged and (c) by exploring an electrochemical method to monitor the instigation of these unsolliceted degradation.