"It's really an exciting development in the study of objects of art," said Jennifer Mass, a scientist and art conservator at the Winterthur museum in Delaware. She and several colleagues presented their results at a conference last month of the American Chemical Society.
The soft-toned painting of Wyeth's family doesn't include much detail; it was meant only as a study for a living room mural the artist had once planned to paint in their suburban Chadds Ford home. Under the serene "Study for Wyeth Family mural," however, lies an earlier composition that's menacing and dramatic.
The 1919 illustration was done for a periodical called "Everybody's Magazine." In a short story, a love triangle ends in the death of the villain, whom Wyeth depicts with clenched fists and an evil scowl as he charges his rival.
Wyeth turned the canvas upside down and painted his mural study around 1927. Included is his young son Andrew, who went on to become one of the most prominent American artists of the 20th century before his death earlier this year.
"Publishers sometimes returned the canvases after the magazine was published, so you can imagine they started to stack up after a while," said Christine Podmaniczky, associate curator for the N.C. Wyeth collections at the Brandywine Museum in Chadds Ford. "It wasn't uncommon for him to reuse canvases."
A partial label stuck to the back of the canvas provided enough information to offer a clue of the under-image, Podmaniczky said. A basic X-ray in 1997 confirmed, albeit in fuzzy black and white, the hunch that it was the long-lost magazine illustration.
"What we didn't know was whether it had been painted in black and white or color," Podmaniczky said. "The image (in the magazine) was black and white, and N.C. Wyeth for a time did paint in black and white as well as color."
Enter the synchotron - Cornell University's high-intensity X-ray. Housed in a circular underground tunnel that's a half mile in circumference, the device creates X-rays with up to a million times the intensity of what dentists use.
When the thin beam hits part of a painting, it creates a phenomenon called fluorescence. Naturally occurring elements both have unique fluorescence fingerprints and correspond to certain paint colors: white contains zinc or titanium, green contains cadmium, blue contains cobalt, and so on.
In essence, the X-ray peers under the top paint layer and - millimeter by millimeter - identifies the chemical composition underneath. From there, experts can begin to map out the colors of the hidden painting.
The beam is as fine as a human hair, so it took scientists a week to move it around N.C. Wyeth's canvas and "read" the elements across the surface.
There are prototypes that could potentially speed up that process "by a factor of 100," said Sol Gruner, Cornell physics professor and director of the synchotron facility.
"That could make it possible to look at paintings more routinely," he said. Today, the synchotron more commonly is used in the bioscience, medical research and pharmacological fields.
Mass, the Winterthur scientist, hopes the Wyeth project will be the first of many.
"There are a few paintings we have our eye on, including a Caravaggio and a Van Gogh," she said. "It's thought that 20 percent of (fine art) paintings have another painting underneath ... there's great potential to study many more works."
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