The secrets of 17th century artists can now be revealed, thanks to 21st century signal processing.

Using modern high-speed scanners and the advanced signal processing techniques, researchers at the Georgia Institute of Technology are peering through layers of pigment to see how painters prepared their canvasses, applied undercoats, and built up layer upon layer of paint to produce their masterpieces.

The images they produce using the terahertz scanners and the processing technique - which was mainly developed for petroleum exploration - provide an unprecedented look at how artists did their work three centuries ago.

The level of detail produced by this terahertz reflectometry technique could help art conservators spot previous restorations of paintings, highlight potential damage - and assist in authenticating the old works.

Beyond old art, the nondestructive technique also has potential applications for detecting skin cancer, ensuring proper adhesion of turbine blade coatings and measuring the thickness of automotive paints.

"This technique allows us to see at high resolution what is beneath the surface of a painting, to assess in depth what kind of technique has been used, and to determine what defects may be present," said Alexandre Locquet, an adjunct professor in Georgia Tech's School of Electrical and Computer Engineering and a researcher at the Georgia Tech-CNRS international laboratory in Metz, France.

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