T-rays to help solve art mysteries

ANN ARBOR, Mich., Feb. 23 (UPI) -- U.S. researchers are testing the use of T-rays, pulses of terahertz radiation, to help art historians find murals hidden behind coats of paint in old churches.

A team of engineers from the University of Michigan plan to take their equipment to France next month to help archaeologists examine a mural discovered recently behind five layers of plaster in a 12th century church, the university said in a release.

The researchers said T-rays can also illuminate penciled sketches under paintings on canvas without harming the artwork. Study author John Whitaker said terahertz imaging is non-ionizing and its rays aren't strong enough to form charged particles that cause damage like X-rays.

"It's ideal that the method of evaluation for historical artifacts such as frescoes and mural paintings, which are typically an inherent part of a building's infrastructure, be non-destructive, non-invasive, precise and applicable on site," study author John Whitaker said in a statement. "Current technologies may satisfy one or more of these requirements, but we believe our new technique can satisfy all of them."

The research was published in the journal Optics Communications.