D'Imporzano (Earth Sciences) studied the isotope ratios of the lead white in paintings, a pigment widely used until the twentieth century. The analysis reveals information about the geographical origin of the pigment that can be linked to trade routes, understanding the period and place in which a painting was produced, and the presence of any later restorations, and whether a painting is a forgery.
Together with the Rijksmuseum, D’Imporzano and Davies analysed works by Vermeer as part of an international project to study the work of the Dutch master. The scientists compared the isotope ratios from samples of eight undisputed paintings by Vermeer, one overpaints from the Girl Reading a Letter at the Window, and one unattributed Vermeer’s painting The Guitar Player to the existing lead isotope ratios database built at the VU geochemistry lab to investigate which lead white the Dutch master used and what new information this provides about his work.
Derbyshire
Analysis of Vermeer's works shows that he used lead from England, likely from the Derbyshire region, like many other seventeenth-century Dutch painters. The lead white he used matches the lead white used and produced in the Netherlands when Vermeer was active (between 1650 and 1675).
Overpainted
The Girl Reading a Letter at the Window was fully restored in 2021, and it was found that the image of Cupid present in the painting was a later addition, potentially not by Vermeer. The lead isotope analysis of the lead white in the overpaint demonstrates that the area has a slightly different composition than the lead white from the original painting, alas, still within the range of seventeenth-century Dutch lead white. This isotopic difference can be an indication that the overpainting was a later addition, not by Vermeer, but it is impossible to date it precisely.
The research was at the Vrije Universiteit Amsterdam in the Clean lab and Mass spectrometry laboratory of the Earth Sciences department, now NIGeL. The research is presented in the book Closer to Vermeer: New Research on the Painter and His Art.