19th & 20th Century Zinc White Paints: Multidimensional Physico-chemical Characterization
IOM3 SEC Group annual Art Lecture series.
The talk explores the properties and use of zinc white oil paints, from the nano- and micro-scale up to the macro-scale of artworks. It is based on the PhD thesis of the speaker performed at the Centre de Recherche et Restauration des Musées de France at the Palais du Louvre in Paris (France) in 2020-24.
Zinc white (ZnO), a modern pigment developed in the late 18th century as a non-toxic alternative to lead white, was adopted in oil paint in the middle of the 19th century. Initially used alongside lead white, its lower covering power and brilliance made it a choice for colour blends, highlights and grounds, and it was also used in impastos for its rheological properties. It can cause condition issues, for example, due to the formation of zinc soaps. Knowing the pigment is, therefore, crucial for technical studies and artwork conservation.
This research focused on two areas: the study of the physico-chemical properties of zinc white and the extent and modalities of use of the pigment. A corpus of ancient and modern zinc white-based artists’ materials (eg pigment powders, paint tubes) was characterised (ie composition, particle morphology and size, luminescence) to tackle the first research axis, and around 80 artworks were analysed to address the second, together with documentary research and a survey among heritage professionals.
This research constitutes a reference on the physico-chemical properties and use of zinc white; it provides information on the material history of the pigment and modern artworks, opening up new perspectives for artwork conservation and authentication.
