By Kevin Stark and Tim Rosenberger
Vincent Van Gogh’s famous paintings of his bedroom used to have purple walls and, like detectives, scientists Francesca Casadio and Marc Walton have the evidence to prove it.
How can the artist’s paint serve as physical evidence of the world in which it was originally applied so long ago?
How can the microscopic analysis of paintings provide key insights into the lost techniques and colors? Provide insight into a forgery? And help determine how a work has faded over time?
These are the clues Casadio and Walton examine with an innovative research team. Using forensic methods, researchers studying ancient Roman portrait paintings, Van Gogh’s famous “Bedroom” paintings, and other works are revealing specific details about the work and the artists, discoveries that art historians are making with scientific imaging that can see inside the paint.
One method involves the use of X-ray imaging that interacts with the atoms of the chemicals present in the paint. The atoms emit back, and the researchers are able to read the color pigments that are present in the section of the painting they are analyzing.
“We are starting to get inside the head of the artist and how they might compose these paintings,” said Walton Sunday at the American Association for the Advancement of Science conference.
Walton, a professor of materials science and engineering at Northwestern University, is working with colleagues including Casadio at the Center for Scientific Studies in the Arts at the Art Institute of Chicago. Casadio is the center’s co-director and chief conservation scientist at the Art institute.
The imaging work means scientists can peel back the years to determine how the historic portraits from Tebbtunis, for example, were made. They can identify degraded color pigments used in the background (Egyptian Blue), the specific animal fur or hair used for the paint brush (likely from a squirrel and definitely not from a cow), and what region of the world the wood substrate had to be imported from (Central Europe).
Van Gogh’s Bedroom
Vincent Van Gogh’s famous “Bedroom” paintings, depicting his bedroom in his Arles home, have been the subject of examination for decades.
The exhibit “Van Gogh’s Bedrooms” that opened at the Art Institute this weekend, brought together the three paintings – from museums in Amsterdam, Chicago and Paris – for the first time in North America. Material analysis allowed the scientists to uncover secrets that could shed new light on these well-known masterpieces.
Casadio, a chemist, said the 19th century saw an explosion of color, and Van Gogh infused his colors with his emotions. But after Casadio examined the color around the edges of the painting that had been protected by the frame and analyzed the molecular composition of the color, it was clear the red in the pigment had faded. Add red to the pigment of the seemingly blue walls and you get purple.
The exhibit shows how science suggests the paintings originally looked.
Casadio highlighted some of the techniques during a Feb. 1 tour for Northwestern students.
“The Bedroom” pieces were painted by Van Gogh during three distinct periods: the first (from the Amsterdam collection) shortly after moving into his home in Arles, France in 1888, the second (at the Art Institute) during his stay at a Saint-Remy asylum in 1889, and the smaller, third painting (from Paris) a few weeks after he made the second. The three works are filled with Van Gogh’s distinct use of color, which was an extremely important tool to the artist.
The Art Institute began research on “The Bedroom” paintings in 2008. Since then, various techniques have been utilized to discover new information and detail hidden in the paintings.
In order to read the pigments, they need to be inorganic. These mineral based pigments are much like bones, dense enough to show up. Organic pigments, on the other hand, function like human skin and are transparent, Casadio said.
Outside of Academia
Material examination of paintings is a technique being employed outside the ivory tower of academia for museums, galleries and collectors. And, the devil is in the details. That is, in the hair from 30 house cats.
Clementine Hunter was a house servant and cook on a plantation in Louisiana. In the 1960s and 1970s, she started painting—on everything, Masonite, cardboard, and other materials. She quickly became a renowned folk artist known for depicting the Southern experience of African-Americans, especially women.
Originally, Hunter sold her colorful, patterned paintings for mere dimes, but her works now sell for from $5,000-$10,000. The paintings have inspired numerous fakes, such as sophisticated renditions painted in Hunter’s style by artist William Toye and his wife Beryl Ann Toye. The Toyes sold their work as Hunter originals.
The fakes were so good it was difficult for the the art forgery arm of the Federal Bureau of Investigation— the Art Crime Team—to decipher real from replica. “There was no good way of doing this except for a very difficult process of elimination,” said FBI art crime team program manager Bonnie Magness-Gardiner.
That is until the paintings were examined with careful scientific instruments and a clear difference emerged: cat hair. The Toyes had tens of cats in their home and Hunter had not.
The shedding felines left evidence in the paint on the forged works, and the cat hairs are a clear indicator of original from farce.
The Toye couple plead guilty to charges in 2011 and were sentenced to probation and ordered to pay hundreds of thousands of dollars for restitution to the victims of the fraud, Magness-Gardiner said.