Testing of Samson
Meloni took a few paint samples, each the size of a pin head, from different parts of the painting. She then mounted them into small blocks of resin that could be studied under the scanning electron microscope.
In one of the samples, Haswell and Meloni found "green earth", a pigment not extensively used in 17th century paintings, but encountered a lot on the late works of Jan Steen. They also found the presence of a double-ground layer, or base layer, which is also seen in other late works of Steen.
The painting was indeed real. "We found some really nice indicators that allowed us to place the painting in a group of works created by Steen in the 1670s," says Meloni.
Examining the painting also revealed the presence of pentimenti — an Italian word for visible traces of changes made by the artists during the painting process. Art historians see pentimenti as evidence that the artist had altered his work during the painting process.
"If you are copying a painting then you just look at it and make a copy," Meloni explains. "But if the painting is a genuine work of art then you’ll see evidence that the painter has changed his mind while painting."
The condition of the painting was particularly striking. "It was a bit dirty and had some layers of dark varnish that needed removing, but apart from that it was quite untouched," she says. One of the paint layers even contained a long hair. "Of course, you can never say for certain, but Jan Steen’s self-portraits do show him to have long, dark, wavy hair," adds Meloni. "I like to think that it comes from him."