Jennifer Mass and colleagues note in the new study that many great artists re-used canvases or covered paintings with other paintings. They did this in order to save money on materials or to let the colors and shapes of a prior composition influence the next one, she says. Art historians believe that several of Wyeth’s most valued illustrations have been lost from view in that way.

One of these so-called lost illustrations depicts a dramatic fist fight and was published in a 1919 Everybody’s Magazine article titled “The Mildest Mannered Man.” Using simple X-ray techniques, other scientists previously showed that Wyeth had covered the fight scene with another painting, “Family Portrait.” But until now, the fine detail and colors in the fight scene have been lost from view. Nobody has seen the true image except in black and white reproductions.

The new instrument, called a confocal X-ray fluorescence microscope, was developed at the Cornell High Energy Synchrotron Source (CHESS) national X-ray facility. The instrument reveals minute details in hidden paintings without removing paint samples. It shoots X-ray beams into a painting and then collects fluorescent X-ray “signals” given off by the chemicals in the various paint layers. Scientists can link each signal to specific paint pigments. In addition to revealing the original image, the method is providing new information on Wyeth’s materials and methods. The same technique may ultimately reveal hidden images in paintings by other famed artists, the researchers say.