4. Analysis of Leonardo da Vinci's paintings

X-ray fluorescence can provide information on the stratigraphy of paintings by modeling the nature and composition of the layers. Leonardo da Vinci's works in the Louvre have been analyzed using this technique, focusing on the pattern of facial shadows. Their main characteristics are presented in the table 1 .

We have focused in particular on the technique used to create the flesh tones. This choice is justified firstly by the fact that these are the central areas of the works, to which Leonardo took particular care. Secondly, these are often well-preserved areas whose stratigraphy is fairly similar from one work to another, which will facilitate our approach.