Lasers Used to Test Whether Painting 'Signed by Da Vinci' Is Genuine

Scientists have used lasers to study an old painting that may have been made by Leonardo da Vinci, one of history's most famous artists. The painting shows the Roman Emperor Domitian and is signed "L daVinci." Researchers from Uppsala University in Sweden say the laser technology they used could help experts figure out whether historic artworks are real or fake.

The painting was first sold at Christie's auction house in London in 1928 and 1929. Back then, it was believed to have been made by a Renaissance painter named Titian. Later, experts took a closer look and found a hidden signature that read "L daVinci," along with a Latin word that likely means "painted." The signature was very hard to see because it blended into the background and only appeared when the painting was lit from just the right angle.

To study the painting, scientists used a method called Raman Spectroscopy. This technique shines laser light onto a surface and reads how the light bounces back to reveal what materials are present. The researchers also looked at tiny samples from different parts of the painting under a microscope. This helped them figure out exactly which pigments, or coloring materials, had been used.

In total, scientists found 13 different pigments in the painting. Twelve of them were traditional pigments that had been used during the Middle Ages and the Renaissance, which means they were available during the time of both Da Vinci and Titian. The black pigment used in the signature was carbon black, a material that has been around since ancient times.

However, there was one problem. Scientists also found a pigment called Prussian blue, which is a bright blue color that was not invented until the early 1700s. Since Da Vinci lived from 1452 to 1519, he could not have used this pigment. Researchers think someone may have added the Prussian blue later when the painting was repaired or touched up. X-ray scans of the painting supported this idea, showing signs of changes in the areas where the Prussian blue was found.

Researcher Jakob Thyr said that finding a newer pigment in one part of a painting does not automatically mean the artwork is a fake. He explained that it is very common for old paintings to be fixed up or restored over the years. Parts that are damaged or faded are often repainted, which can introduce newer materials into an otherwise very old work.

Even so, the tests could not fully confirm who actually painted the artwork. The scientists said that their work showed how tools from the field of materials science can be used to learn more about art and ancient objects. Dr. Thyr believes this kind of scientific analysis will become more and more common in the art world in the years to come.