DaVinci, Caravaggio, VanGogh and Monet are just a few of the artists whose works attract thousands of visitors every year. However these paintings often suffer from damage due to aging and exposure to the elements. What once was a masterpiece on a church ceiling or wall often requires a highly skilled restoration team to return it to its original form – a process which is being aided by researchers at McGill University in Quebec, who have used a technique called "photoacoustic infrared spectroscopy" to identify the composition of pigments used in art works.

The technique uses Alexander Graham Bell's 1880 theory that solids emit sound when exposed to light. The team at McGill are the first to apply the technique to inorganic pigments commonly used in paints. This provides a better understanding of the chemical composition, which in turn helps establish the best method of preserving important artworks.

"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," explained Dr. Ian Butler, lead researcher and professor at McGill's Department of Chemistry.

Without this understanding restoration attempts in the past have often lead to more damage than if they had left the work untouched.

To date Butler’s team have recognized 12 historically prominent pigments dating back decades and even centuries and they hope 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.

The team now hopes to find partners interested in developing this technique into standard preservation practices.