Mural painting in Tuscany during the Middle Age: a spectroscopic investigation on pigments and painting technique

The inspection of pigmenting agents and painting techniques are some of the main archeological questions posed by artworks as wall paintings and frescoes. The identification of peculiar pigments as well as the discrimination among decorative techniques allows supporting archeological interpretations about construction phases and possible restoring actions. In the matter in fact, the possibility to acquire such information requires the application of a combined archeological and archeometric approach, supporting the historical and architectonical evidences with analytic data. That’s the case of San Genesio church (San Miniato, Pisa) wall paintings, explored in the present study by spectroscopic methods, i.e.: Raman spectroscopy and portable XRF fluorescence, supported by classical minero-petrographic analysis. The studied materials consist in red, yellow, green painted fragments founded in the collapse layers of the presbytery and crypt. The church, located in the Arno valley, along the Via Francigena and the road that linked Florence to Pisa, was built in the late 7th century and enlarged between the 10th and the second half of the 12th century, when a rich village developed near the religious building. On the basis of the archeological evidences, it is possible that the wall paintings are related to the decoration of the 11th-12th century presbytery or crypt. The obtained results data have been employed to unveil raw materials and painting techniques, possible different construction phases in San Genesio church and, finally, support the archeological studies on the technological evolution of mural painting in Tuscany during the Middle Age.