Laser cleaning

The laser removal of unwanted layers constituted by materials of diverse origin (organic and inorganic), assembled in mixtures (e.g., thick pollution, burial accumulations) or in layers (e.g., multiple protective, metallic, dirt and/or overpaint layers) on weathered, even fragile, original surfaces. The laser action is based on the process of ablation or vaporization and it offers unique possibilities in surface cleaning as it entails precise control, material selectivity and immediate feedback. These attributes are particularly important in Heritage conservation and within the last twenty years, lasers have evolved as exceptionally practical, and at the same time, delicate cleaning tools. This FIXLAB possess a variety of pulsed laser sources emitting in the ultraviolet, visible and infrared spectral ranges with pulse duration in the nanosecond and femtosecond regimes. Laser cleaning investigations are carried out in the installation on a large variety of heritage materials, including varnished paintings, polychromes on wood or stone, heritage stone with pollution and/or biodegradation crusts, metal substrates with corrosion layers, paper and parchment based documents and other materials. Studies aim at determining the most adequate laser parameters and the most convenient methodologies (choice of laser wavelength, dual irradiation schemes, etc.) for a safe laser cleaning treatment according with material properties and state of conservation.