A team of European scientists unveiled a new method this week of extracting images hidden under old masters’ paintings without harming them, recreating a colour portrait of a woman’s face unseen since Vincent van Gogh painted over it in 1887.
While not exact in every detail, the image produced shows a woman’s head that a Van Gogh expert said may be that of the model in a series of portraits leading up to the 1885 masterpiece The Potato Eaters.
Van Gogh often reused canvas to save money, either painting on the back or over the top of existing paintings. Experts believe roughly one-third of his works hide an earlier painting underneath.
Joris Dik, a materials scientist from Delft University, and Koen Janssens, a chemist from the University of Antwerp in Belgium, combined science and art to engineer a new method of looking at hidden paintings, using high-intensity X-rays and an intimate knowledge of old pigments.
Art historians have for years been using X-rays to look at artworks hidden under other paintings, a technique resulting in a fuzzy, black-and-white image.
Dik and Janssens took a different approach with Patch of Grass, a small oil study of a field that Van Gogh painted in Paris while living with his brother Theo.
They used high-intensity X-rays from a particle accelerator — which physicists usually use to study subatomic particles — to compile a two-dimensional map of two different types of metal atoms on the painting beneath Patch of Grass.
Knowing that the mercury atoms were part of a red pigment and the antimony atoms were part of a yellow pigment, they were able to chart those colours in the underlying image.
”We visualised — in great detail — the nose, the eyes, according to the chemical composition.” Dik said. He said scanning a roughly 18cm square of the larger portrait took two days at an accelerator in Hamburg, Germany.
Teio Meedendorp, an independent Van Gogh expert in Amsterdam, said the woman pictured under the current painting was probably painted between November 1884 and March 1885, while Van Gogh lived in the Dutch village of Nuenen.
In that period he painted a series of heads in what Meedendorp called ”oil lamps and candlelight”, followed by the famous Potato Eaters of April 1885.
The painting under Patch of Grass adds weight to the theory that Van Gogh mailed paintings from The Netherlands to his brother Theo and, after moving to Paris to join Theo, found the old works and painted over them.
Both Dik and Meedendorp were excited about the prospect of using X-ray fluorescence to probe paintings by Van Gogh and other famous artists, such as Rembrandt and Picasso.
”I was really surprised by the quality of the image, which is really promising for the future of research,” Meedendorp said.
However, scanning other paintings may be difficult since the technique requires a particle accelerator, and few exist in the world — and none in The Netherlands.
Dik and Janssens’ scientific paper was published online on Wednesday in the Journal of Analytical Chemistry. — Sapa-AP