Using lasers for cleaning ceramic and plaster patrimonial objects

International audience; Traditional cleaning techniques (sandblasting, chemical, ...) turn out to be ineffective or damaging on some ceramics and plaster objects. It's especially true on outdoor ceramics covered with black crust or indoor biscuits wares and plasters exposed to dust and repeated handling. The use of lasers to remove dirt, such as for stone, has then been considered. This paper study the behavior of these materials under the impact of different type of lasers irradiation (Nd:YAG first and third harmonic, excimer,...). According to the type of dirt and underlying material, the effectiveness of cleaning depends on the laser wavelength and its energy density. The results are satisfactory with no damage and no coloration change on plaster cleaning by Nd:YAG third harmonic