Art conservationists cleaned the two angels on the left with traditional restoration methods. They cleaned the one on the right using an advanced laser technique, which produced better resultsA laser technique that removes unwanted tattoos has been used to clean several famous works of art, including wall paintings.
The technique removes material from a solid surface by vaporising it with a laser beam. Called laser ablation, it can lift dirt without damaging the underlying surface.
Long used to preserve stone sculptures and metal artifacts, it has now been applied to the delicate wall paintings of the Sagrestia Vecchia and the Cappella del Manto in Santa Maria della Scala, Italy.
Dr Salvatore Siano and Renzo Salimbeni from the Applied Physics Institute-CNR in Italy, described the results in the journal of the American Chemical Society.
Dr Siano said: 'This is a more delicate situation than metals or stone as the pigment is much more fragile.'
The pigments of paintings endure laser light better than they do the corrosive and damaging chemicals that have been traditionally used to clean them.
Different lasers are used for different paintings because the frequency and the duration of the pulses affect how localised areas are heated.
In some cases a long heating can be harmful while a short heating is detrimental in others.
The technique was also used on masterpieces like Lorenzo Ghiberti's gilded bronze panels Porta del Paradiso and Donatello's bronze David.
'This was the first time a well recognised masterpiece was treated with laser cleaning,' Dr Siano said.
The team also reported encouraging results of laser cleaning underwater for materials that could deteriorate if exposed to air.
source: dailymail