Color and painting techniques in Etruscan architectural slabs

In 2016, a huge amount of archaeological materials, mainly painted architectural slabs, were taken back in Italy from the Carlsberg Glyptotek of Copenhagen and from the collection of a Swiss art dealer after an investigation of Italian authorities on the illegal antiquities trade. According to style and typology, part of these materials are supposed to come from the UNESCO archaeological site of ancient Caere (Cerveteri); actually, the site was an important Etruscan center where the tradition of painted architectural slabs is attested with a relevant production from the second half of the VI century B.C. Overall, the corpus consists in 1779 fragments grouped in fourteen slabs, turning in homogenous figurative scenes and exhibiting a polychrome decoration. Due to the fragmentary nature of documentation related to these artefacts, relevant questions on attribution, provenance determination and authenticity of them are currently opened among archaeologists and scientists. A non-destructive analysis campaign was therefore performed by portable XRF and Raman instrumentations with the aim to characterize pigment layers and support the interpretative analysis, in the lack of a proper literature references on raw materials and manufacture technology; moreover, XRD and micro-Raman spectroscopy were carried out on micro-samples to go deeper inside in the material characterization. The multi-analytical investigation allowed to open interesting questions on color palette and painting techniques. A recurrent use of the same pigments was evidenced through the corpus, even with some differences especially in the black pigment layers; the different figurative motifs allowed to classify the fragments in several groups, possible related to as much as different artistic phases, use and/or manufacture centers. Actually, complementary investigation on bulk were performed to unveil possible correlation between figurative cycles and provenance sites. Comparative studies with reference materials from Cerveteri area were also performed, providing clues for a discussion on their authenticity.