A non-invasive campaign was carried out on paintings by Grubicy and Benvenuti and focused on works which were selected based on archival research. Imaging (UV Fluorescence, UV false colour, IR reflectography, IR False colour Photographic; IR multispectral reflectography imaging, and Fluorescence Lifetime Imaging (FLIM)) were complemented by point-like analysis (using UV-VIS absorption and emission, Near- and Mid-Infrared, Raman and X-ray Fluorescence Spectroscopy) and micro-photography in the visible and infrared range. The complementary investigations allowed significant insights into the working processes adopted and the materials employed by the artists, and confirmed results from the study of sources and of materials from the atelier.