Arts & Culture: Beneath a Painting’s Surface

A portrait of a bearded man in a jacket and bow tie hides beneath Picasso’s The Blue Room. A peasant woman stares out from under Patch of Grass by Van Gogh. These images, invisible to our eyes, have been uncovered by scientists studying paintings using infrared light and x rays, which both can penetrate paint layers. But paintings examined in this way are typically removed from gallery walls and taken to a university or facility that has the necessary tools—the Van Gogh painting was transported from a museum in Amsterdam to an x-ray synchrotron in Hamburg. The process is time-consuming, costly, and irritating to museumgoers, who are unable to gaze on the artwork for a few months. As a result, very few paintings end up being investigated by scientists. Physicist Charles Falco hopes to change this with portable scientific instrumentation.

For the last decade, Falco, a professor of optics at the University of Arizona and a collaborator of English artist David Hockney, has been traveling the world snapping paintings and art objects on display with a homebuilt infrared camera. In just a few hours of his time, Falco can capture a room full of artwork—something that might otherwise take scientists years. Recently he added to his tools a portable Raman spectrometer, an instrument that can determine the chemical composition of paint pigments. His ultimate goal is to develop a suite of compact instruments that can be carried anywhere to uncover the secret lives of artworks in a flash.