https://phys.org/news/2019-01-secret-rembrandt-impasto-unveiled.html

The European Synchrotron, ESRF, played an essential role in these findings. The team sampled tiny fragments from the Portrait of Marten Soolmans (Rijksmuseum), Bathsheba (The Louvre) and Susanna (Mauritshuis), three of Rembrandt's masterpieces. Using the ESRF's beamlines, they quantified the crystalline phases in Rembrandt's impasto and in the adjacent paint layers, modelled the pigment crystallites morphology and size and obtained crystalline phase distribution maps at the microscale.

The samples were less than 0.1mm in size, requiring the small and intense beam delivered by the synchrotron. The scientists analysed them on two ESRF beamlines, ID22 and ID13, where they combined high-angular resolution X-ray diffraction (HR-XRD) and micro-X-Ray diffraction (µ-XRD) . "In the past, we have already successfully used the combination of these two techniques to study lead-white based paints. We knew that the techniques can provide us with high quality diffraction patterns and therefore with subtle information about paint composition," explains Marine Cotte, scientist at the ESRF, 2018 Descartes-Huygens Prize laureate for her research on art conservation.