How Airport Scan Tech Reveals Hidden Artwork
CREDIT: Podriv Ustoev | Shutterstock
Hundreds of years ago, artists would paint over previous works, seemingly erasing them from art history forever. But using technology commonly found in airport body scanners, researchers now have a method of discovering these hidden relics without harming the overlying artwork.
Today, some artists gain renown with garish sculptures or bizarre performance pieces, but hundreds of years ago, painting was all the rage. Then, as now, materials were expensive, and artists generally didn't have much money to throw around. Painting over previous works was a simple way to save money.
About 3,500 years ago, some budding virtuoso had the bright idea to spread plaster over a wall and paint a scene before the material had time to set. The paint dries along with the plaster, making the painting, called a "fresco," an integral part of the wall, rather than just a decoration on its surface.
One such fresco was 19th-century collector Giampietro Campana's "Trois hommes armés de lances" ("Three men wielding spears"), which he restored after purchasing only fragments of the original. This fairly innocuous tableau depicts three Romans standing shoulder-to-shoulder holding their weapons.
Since the fresco came to Campana from Italy, art historians have long suspected that there may be an ancient piece of Roman artwork lurking just underneath the surface. J. Bianca Jackson, a postdoctoral research assistant at the University of Rochester, used her expertise in terahertz spectroscopy to help.
Terahertz spectroscopy employs directed electromagnetic radiation to objects that are invisible to the naked eye. The process uses terahertz radiation, which lies just between infrared and microwave wavelengths on the electromagnetic spectrum, and poses less risk to artwork than even visible light. The pharmaceutical industry, Jackson explained, uses this technology to test the integrity of pills, and airports utilize it to scan underneath travelers' clothing.
Exposing the fresco to terahertz spectroscopy turned out to be an exhausting process, with hours upon hours dedicated to scanning only a square foot or so of space. The results, however, were well worth the effort. [See also: Technology Conference Shows Off Interactive Art]
"We were amazed, and we were delighted," Jackson said. "Underneath the top painting of the folds of a man's tunic, we saw an eye, a nose and then a mouth appear. We were seeing what was likely part of an ancient Roman fresco, thousands of years old." Instead of three men wielding spears, the fresco originally showed just one man whose identity is still a mystery.
Jackson has also used the technology to examine early human artwork in modern-day Çatalhöyük, Turkey. A number of prehistoric works now exist behind protective layers of plaster, making a comprehensive examination almost impossible. Terahertz spectroscopy can pierce these barriers and give researchers some insight into the art from just before the dawn of modern civilization.
During your next trip through airport security, it might be comforting to know that the same technology hassling you is also unlocking the art world's greatest mysteries. That’s cold, shoeless comfort, to be sure, but comfort nonetheless.
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