THE SAN PIETRO MARTIRE TRIPTYCH BY BEATO ANGELICO: MATERIALS CHARACTERIZATION BY MEANS OF INTEGRATED NON-INVASIVE SPECTROSCOPIC MEASUREMENTS

This work presents some results showing how the integrated use of non-invasive spectroscopic techniques is extremely useful for deepening the knowledge of an artwork. The object under study is the Triptych of San Pietro Martire by Beato Angelico, (152 cm × 172 cm × 10 cm), a panel painting from the San Marco Museum in Florence. The analytical protocol was developed to characterize the materials used by the artist and to clarify some doubts concerning the dating. Fiber optic reflectance spectroscopy (FORS) was useful to obtain information concerning the composition of the artist's palette, composed of pigments commonly used in15th century Italian easel painting. Of particular interest, is the presence of green areas obtained by a mixture of azurite and lead and tin yellow. These data suggest that the painting could be dated back to the artist's early period, when Beato Angelico was in contact with Lorenzo Monaco, while in his mature works, green parts were commonly painted with green pigments. X-ray fluorescence (XRF) measurements integrated and completed the FORS results, allowing to better characterize most of the pigments. Furthermore, investigations carried out by portable total reflection infrared spectroscopy (TR-FT-IR) provided information about the organic materials used as binders, both in the ground and in the paint layers.