Successful applications of Nd:YAG lasers in conservation and knowledge of art and historical artefacts

Cleaning using pulsed Nd:YAG laser is the most important contribution of physics to the conservation of Cultural Heritage. Along the last decades, it moved from sporadic embryonic tests to an initial level of spreading. A significant development of this field has been provided by the "optimised pulse duration approach". Very peculiarly, the domain of major interest for laser ablation in conservation ranges between 10 ns-100 µs. Actually, the upper range 100 ns-100 µs, typically not used in other ablative applications, provides significant advantages for controlling undesired effects. To date, laser cleaning has been employed in a number of conservation works through rigorous multidisciplinary validation studies. The most of them were addressed to stone artefacts. Here, the main case studies of the Florentine experience on metal artefacts and wall paintings are briefly discussed. The present case studies also provided the opportunity to test and extensively apply a novel portable laser induced plasma spectroscopy instrument to characterise alloy compositions and corrosion phenomena, which significantly extends the impact of the laser technologies in the field of Cultural Heritage.