A few days ago Gabrielle and Abby from the conservation section borrowed one of the plaster casts from the archaeology collection to take to a workshop about laser cleaning at the Conservation Centre in Liverpool. Gaby kindly took some photos and drafted some text to explain what is involved.
Lasers have been used to clean stone work and sculpture in conservation since the 1970s. The laser is a highly concentrated and strong light beam which is fired at the object and heats up the dirt layer making it expand quickly and so forcing it from the surface. The light is very directional and only affects a few microns of the surface at a time so is easy to control and does not damage the surface. The operator can also control the amount of energy which hits the surface by moving the pen closer and further away from the object.
As well as stone there are many other materials for which laser cleaning is being tested and developed including metals, paper, and organics like wood, feathers and fabric. It has to be remembered that lasers work very effectively in certain cases but many objects and materials are unsuitable for laser treatment or the dirt and dust is unresponsive to the treatment. So the laser is only another tool in the conservator’s tool kit and should be considered equally alongside other treatments.
Find out more in a future Blog!