Scientists say that a missing ingredient in paints helps to explain how Rembrandt achieved the layered effect in several of his paintings. For many years, it was thought that painters used ingredients usually available to Rembrandt’s seventeenth-century peers – cerussite, lead white pigment, as well as linseed oil. However, those who used the X-ray technology in order to analyze samples taken from his three famous paintings were stunned to find out a mineral that is more commonly found these days in car paint.
The team of Dutch and French scientists discovered plumbonacrite in Rembrandt’s paint, after analyzing samples taken from his works of art. One of them is the “Portrait of Marten Soolmans”, which you can see on your Rijksmuseum tour.
After removing these samples, the scientists applied them to high-end imaging techniques at Grenoble’s European Synchrotron. The minuscule scrapings subjected to X-rays revealed the chemical composition of his artworks’ paint, employed for each different layer.
Plumbonacrite was found in “impasto” layers of his paintings, not the in the paint’s base coat. Victor Gonzalez, a researcher at the Rijksmuseum, and the Delft University of Technology shared the team’s surprise at finding out the crystalline substance’s presence.
He said, “We didn’t expect to find this phase at all, as it is so unusual in Old Masters paintings. What’s more, our research shows its presence is not accidental or due to contamination, but the result of an intended synthesis.”
As yet, plumbonacrite had only been found in twentieth-century paintings, and Vincent van Gogh’s “Haystack under a Rainy Sky”. It is nowadays used in the segment of car manufacturing as a color preserver for orange and red paints, whereas modern painters often combine a synthetic version into the white paint in order to give it a “pearlescent” effect.
The authors of this research paper, which was published in the Angewandte Chemie journal, speculate that it found its way into the paint of Rembrandt through the use of lead oxide by the artist, or litharge, in order to thick up paints.
The method of layering the oil paint thickly onto old paintings to give texture to them, add depth to shadows and brilliance to highlights, had actually been mastered by the painter named Titian. Rembrandt took this method on, using it in order to accentuate the detail on jewelry and robes, which he used in paintings, and gave a life-like quality to his subjects’ skin.
The researchers said that their latest discovery would shape how the Dutch master’s paintings are restored as well as conserved. However, Rijksmuseum’s Annelies van Loon said this trial is too narrow to conclusively prove the composition of all of his paints. She added the team of researchers plans to run similar trials on paintings by seventeenth-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,” van Loon said.