Zinc white is a pigment that, due to its non-toxicity, was introduced as an alternative to lead white in the mid-19th century. It has been extensively used ever since, and can be found back in a wide range of works from painters such as Van Gogh, Mondrian, and Gauguin. Some disconcerting degradation phenomena, such as the delamination of paint layers, have been linked to the degradation of zinc white, making the understanding of its degradation processes a research topic of high interest.
In this project we aim to develop and apply novel analysis techniques that can provide a detailed understanding of the degradation of zinc white in oil paint. A close collaboration with IPANEMA allows for access to high-end synchrotron-based methodology, and the know-how with regards to its application to cultural heritage materials.
So far, we have been working most intensively on the combination of deep UV photoluminescence microscopy and microspectroscopy, as well as the processing and statistical analyis of the datasets that are obtained using this technique. The datasets contain information of high lateral resolution and chemical specificity, which makes it possible to visualise degradation products, and discriminate between different types of zinc white, as well as various other pigments (Hageraats et al. 2019a, Hageraats et al. 2019b). Recent experimental work has been focused on the study of the intrinsic properties of zinc white. With the use of an X-ray nanoprobe, we managed to reveal a previously unknown chemical property of the pigment, that can be argued to be directly linked to its reactivity in oil paint (Hageraats et al. 2020).