Laser-induced breakdown spectroscopy for semi-quantitative and quantitative analyses of artworks—application on multi-layered ceramics and copper based alloys

In the present work, we report on the analyses of different types of artworks, such as medieval glazed Umbrian pottery and copper based alloys from Roman and modern periods, performed by means of Laser Induced Breakdown Spectroscopy (LIBS). The semi-quantitative analyses on the multi-layered ceramic findings regard glaze, luster and pigment decorations present on the surface. The composition for each decorative layer was determined by estimating the contribution of the ceramic layer beneath the examined one to the whole plasma emission. Two types of ancient luster have been considered: red and gold, while the pigments examined include painted decorations of different blue tonalities. The measured elemental composition of the decorative layers resulted partially correlated with the color of the painted surface, measured by a standard UV-VIS spectrometer. In LIBS analyses of bronze samples, a procedure was developed, which improves data repeatability and extends quantitative measurements to minor elemental constituents. Results of the quantitative analyses gave indications about the manufacturing process of the artwork, its actual degree of conservation and the presence of residual surface decorations.