Scientists 'listen' to paint pigments

MONTREAL, Sept. 2 (UPI) -- A new technique that can "hear" the sound of colors may help art restorers identify the pigments in centuries-old paintings, researchers say.

Canadian scientists at McGill University in Montreal say a technique called photoacoustic infrared spectroscopy can cause the pigments used in artists' colors to emit sounds when light is shone on them, a university release said Wednesday.

"The chemical composition of pigments is important to know, because it enables museums and restorers to know how the paints will react to sunlight and temperature changes," said Ian Butler, a professor at McGill's Department of Chemistry.

The spectroscopy method is based on Alexander Graham Bell's 1880 discovery that solids could emit sounds when exposed to sunlight, infrared radiation or ultraviolet radiation.

The McGill researchers are the first to use it to analyze typical inorganic pigments that most artists use.

The researchers have classified 12 historically prominent pigments by the infrared spectra they exhibit – in other words, the range of noises they produce – and hope the technique will be used to establish a pigment database.

"Once such a database has been established, the technique may become routine in the arsenal of art forensic laboratories," Butler said.