New Light on Old Art
How does an expert know if a painting is by a famous artist, or is a fake? Scientific methods use electromagnetic radiation—visible light, ultraviolet, infrared, and X-rays.
Scientific methods cannot prove that a painting is genuine, but they can prove that it is a forgery. Careful examination may reveal aspects of the painting—the artist's methods or the materials used—that come from a time period later than the supposed date of the painting.
The simplest techniques used to examine paintings are those involving visible light. Looking at a cross section of a paint sample with a microscope or hand lens shows how the artist built up the layers of paint.
Scientists are able to examine the structure of the paint pigment in detail using high-powered microscopes. The structure can reveal whether the pigment is natural or has been made synthetically. Because synthetic paint pigments were not developed until the 1800s, the presence of synthetic pigment indicates the earliest date for the painting.