Non-destructive in situ analysis of polychromy on ancient Cypriot sculptures

The study focuses on the characterization of polychromy on limestone sculptures from Cyprus, attributed to the Cypro-Archaic—end of the Hellenistic periods. Polychromy components were identified by integrating digital microscopy, imaging under ultraviolet (UV) light, visible-induced luminescence (VIL), X-ray fluorescence spectroscopy (XRF) and fibre optics reflectance spectroscopy (FORS). Data acquisition was performed directly in exhibition rooms at the Cyprus Museum (Nicosia) and the Paphos District Archaeological Museum (Paphos). Among the identified materials, there are iron-containing (red, yellow, green) and copper-containing (green and blue) pigments. The precision of pigment identification by non-destructive techniques is discussed, and specific pigment names are proposed: red iron oxide, yellow iron oxide-hydroxide, green earth and Egyptian blue. Interesting results were obtained by VIL, which allowed identifying traces of Egyptian blue otherwise undetectable with the naked eye. Complementary, this study discusses advantages and problems of combined and separate use of portable XRF and FORS, raising the question of their complementarity and interchangeability for the purposes of pigment identification.