Laser cleaning studies on stonework and polychromed surfaces

The research was concerned with the implementation of laser cleaning on stonework. Much research work has been carried out in the past to understand and explain the laser interaction with the stone. It has been shown that the Nd:YAG laser (at 1.064/μm) acts as a self-limiting tool for the removal of the black encrustation on stonework. The main objective of this research was a more thorough understanding of the various cleaning mechanisms. In order to evaluate the advantages of laser cleaning some training on the conventional methods of conservation (air-abrasive, steam cleaning etc.) had been undertaken in restoration at real sites. The laser cleaning effects on alabaster sculpture were studied first followed by work on limestone. Surface and chemical analytical techniques (Scanning Electron Microscopy, Optical Microscopy, X-Ray Diffraction etc.) have been employed to inspect the stone surfaces before and after the irradiation. [Continues.]