Multispectral Remote Digitalisation of Large-Scaled Paintings in Palazzo Chigi of Ariccia

The multispectral study and the digitalisation of large-scaled artworks is often a critical procedure due to the movement of the instrumentation, which need scaffolds, long timing and long data acquisition time, especially when artworks are also placed at large heights, such as painting hung on walls. This is the case of a series of paintings located at the Chigi Palace in Ariccia (Rome, Italy), studied with two prototypal laser scanner systems developed by ENEA. By the use of laser sources in the visible/infrared ranges and the double-amplitude modulation technique, the scanners detect the reflected signals from the investigated object working remotely for the colour-accurate digitalisation and the detection of subsurface features. The Red Green Blue-Imaging Topological Radar (RGB-ITR) system was employed on a large canvas depicting angels with symbols of the Passion of Christ for the remote 3D digitalisation in the visible range, while the Infrared Imaging Topological Radar (IR-ITR) system was endorsed on two paintings belonging to the Four Seasons series for the infrared analysis aimed at the identification of hidden elements and the recovery of features not clearly visible. The obtained results provided precious information on the conservative state and the artistic techniques of large-scale artworks, not studied before by advanced technologies.