'St. Joseph with the Child' by Gian Lorenzo Bernini: A definitive artwork or a preparatory drawing? A multidisciplinary study of the only autograph painting of the Artist, preserved at Palazzo Chigi of Ariccia (Rome)

The artwork “St. Joseph with the Child”, preserved in Palazzo Chigi of Ariccia (Rome), is today the only painting signed by Gian Lorenzo Bernini. In this work, for the first time, an integrated spectroscopic imaging and analysis approach was performed to study and characterize Bernini's wall painting. Complementary in situ analyses, imaging in the UV–VIS–NIR–SWIR range, FT-IR spectroscopy, Raman spectroscopy, laser-induced fluorescence and XRF were performed to obtain information on the state of conservation, the execution technique and the composition of the materials of the painting investigated. The results achieved were discussed and delivered to the conservator of Palazzo Chigi, to plan further restoration treatments and conservation programs. In conclusion, preliminary considerations are presented to define if the painting studied represents a definitive painting or a preparatory drawing.