Dr Marine Cotte, an internationally renowned art conservation expert at the ESRF, explained: “The presence of plumbonacrite is indicative of an alkaline medium. Based on historical texts, we believe that Rembrandt added lead oxide, or litharge, to the oil in this purpose, turning the mixture into a paste-like paint.”
Alkalid paints are quick-drying, lending themselves to building a layered effect on a canvas.
The researches say their discovery will now shape how Rembrandt’s paintings are restored and conserved.
However, Dr Annelies van Loon, of the Rijksmuseum said that the test is too narrow to prove conclusively the composition of all of Rembrandt’s paints, adding that the team now plan to run similar tests on paintings by other 17th-century Dutch masters.
“We are working with the hypothesis that Rembrandt might have used other recipes, and that is the reason why we will be studying samples from other paintings by Rembrandt and other 17th Dutch Masters, including Vermeer, Hals, and painters belonging to Rembrandt’s circle,” she said.