A world group of scientists from the Rijksmuseum, the CNRS, the ESRF the European Synchrotron, the College of Amsterdam and the College of Antwerp, have found a uncommon lead compound (named lead formate) in Rembrandt’s masterpiece The Evening Watch. This discovery, which is a primary within the historical past of the scientific research of work, offers new perception into Seventeenth-century portray method and the conservation historical past of the portray. The research is revealed in Angewandte Chemie — Worldwide version.
The Evening Watch, painted in 1642 and right now displayed within the Rijksmuseum Amsterdam (The Netherlands), is one among Rembrandt’s most vital masterpieces and largest murals. Within the framework of the 2019 Operation Evening Watch, the most important analysis and conservation mission ever undertaken for Rembrandt’s masterpiece, a global analysis group joined forces to review how the portray supplies react chemically and with time.
The group of scientists mixed multi-scale imaging strategies with a view to chemically research the supplies utilized by Rembrandt in The Evening Watch. A X-ray scanning instrument developed on the College of Antwerp (Belgium) was utilized on to the portray, whereas tiny fragments taken from the portray had been studied with synchrotron micro X-ray probes, on the ESRF, the European Synchrotron (France), and PETRA-III facility (Germany). These two sorts of analyses revealed the presence of an sudden organo-metallic compound: lead formates. This compound had by no means been detected earlier than in historic work: “In work, lead formates have solely been reported as soon as in 2020, however in mannequin work (mock-up, contemporary paints). And there, shock: not solely will we uncover lead formates, however we determine them in areas the place there is no such thing as a lead pigment, white, yellow. We predict that most likely they disappear quick, this is the reason they weren’t detected in outdated grasp work till now,” explains Victor Gonzalez, CNRS researcher on the Supramolecular and Macromolecular Photophysics and Photochemistry (PPSM) laboratory (CNRS/ENS Paris-Saclay) and first writer of the paper.
Why did this one not disappear then? For Katrien Keune, head of science at Rijksmuseum and professor on the College of Amsterdam (the Netherlands), this discovering is vital to understanding Rembrandt higher: “In Operation Evening Watch we concentrate on Rembrandt’s portray method, the situation of the portray and the way we are able to finest protect it for future generations. The lead formate offers us beneficial new clues concerning the doable use of lead-based oil paint by Rembrandt and the potential influence of oil-based varnishes from previous conservation therapies, and the advanced chemistry of historic oil work.”
What’s the origin of this compound? Can it present info on Rembrandt’s workshop recipes, or make clear the chemical mechanisms lively within the layers of outdated paint? To reply these questions, the scientists studied fragments taken from The Evening Watch and mannequin samples ready within the laboratory simulating the painter’s formulations.
They labored with the speculation that Rembrandt used an natural medium (linseed oil) containing dissolved lead oxide (PbO litharge) to reinforce its siccative properties. “Due to the distinctive analytical efficiency of the ESRF, the world’s brightest synchrotron mild supply, we may map the presence of formates at a micrometric scale, and observe their formation over time,” explains Marine Cotte, scientist on the ESRF. The spatial group of the compounds on the micro-scale and the dynamics of their formulation made it doable for the researchers to recommend new hypotheses on the chemical circumstances of their in situ crystallisation in outdated paint layers.
“Along with offering info on Rembrandt’s pictorial strategies, this analysis opens up new avenues on the reactivity of historic pigments, and due to this fact on the preservation of heritage,” explains Koen Janssens, Professor on the College of Antwerp.
The subsequent step for the group is to additional research the origin of those formates and see if they may additionally originate from previous restoration therapies.
Word: This analysis advantages from a facilitated entry offered to the historic supplies group to the synchrotron strategies on the ESRF, that has been applied with assist fromthe European Union’s Horizon 2020 analysis and innovationprogramme beneath grant settlement No 870313, Streamline.