New discoveries on Leonardo da Vinci drawings

Leonardo's drawing technique has always been amongst the most fascinating topics in art history. To date, all conclusions on the materials that Leonardo used to perform his graphical works are mostly based on visual investigation. The support of technical analysis in this regard is still very limited. This paper focuses on the investigation - by means of non-invasive Raman and XRF spectroscopy and MA-XRF imaging spectroscopy - of two important drawings that Leonardo completed with the metalpoint technique. The research is part of a broader scientific project on twelve Leonardo drawings belonging to the Biblioteca Reale in Turin, coordinated by the Istituto Centrale Restauro e Conservazione Patrimonio Archivistico e Librario (ICRCPAL) in Rome. The project is aimed at characterization of the material components used and establishing the state of conservation of the artworks. The combination of Raman and XRF results together with the elemental distribution images provided by MA-XRF, allowed for an improved description of Leonardo's drawing technique. It also brought new fascinating insights on the analyzed graphic media, starting from the unusual use of a copper-based metalpoint, up to the peculiar white bone preparation.