Improved microfading device for risk assessment of colour change in Van Gogh’s works

This PhD project dealt with ligth-induced colour changes of paint materials used by Van Gogh in his works. Over the past decades, conservators and curators at the Van Gogh Museum have gathered increasing evidence of colour changes having occurred in Van Gogh’s paintings. For instance, the light-sensitive pigments responsible for these colour changes have been identified and their degradation mechanisms investigated. Additionally, light-ageing experiments on paint-outs were conducted and several attempts to estimate the original appearance of paintings carried out. Yet, our actual knowledge of the timescale of this problem is rather limited. To what extent has the observed fading and discolouration in Van Gogh’s paintings now stabilised? And if still ongoing, how fast does it occur? In other words, can we expect to see colour changes taking place in Van Gogh’s paintings over the next ten years or so? The work performed during this PhD contributes towards providing answers to these questions, by supplying reliable data for light fading risk assessment on which to base decisions regarding the long-term preservation of the paintings. The specific aim of this PhD project was to improve microfading analyses on technical and methodological levels so that it could take us closer towards reliable colour change prediction. Chapter 1 introduces the aspect of colour change in Van Gogh’s works, while Chapter 2 gives an overview of the microfading technique. Chapter 3 focuses on the development of a new microfading system, called stereo-MFT. Chapters 4 and 5 deal with light fading experiments on paint samples.