More than XRF Mapping: STEAM (Statistically Tailored Elemental Angle Mapper) a Pioneering Analysis Protocol for Pigment Studies

Among the possible variants of X-Ray Fluorescence (XRF), applications exploiting scanning Macro-XRF (MA-XRF) are lately widespread as they allow visualization element distribution maintaining a non-destructive approach. The surface is scanned with focused or collimated X-ray beam millimeters less: analyzing emitted fluorescence radiation, also elements present below contribute to elemental image obtained, due penetrative nature X-rays. importance this method in investigation historical paintings so obvious—as obtained can reveal hidden sub-surface layers, including changes made by artist, restorations, without any damage object—that recently specific international conferences have been held. paper summarizes advantages and limitations using MA-XRF considering it an imaging technique, synergy other hyperspectral methods, combining spot investigations. most recent cultural Heritage field taken into account, demonstrating how 2D-XRF maps be great help diagnostic applied on Cultural materials. Moreover, pioneering analysis protocol based Spectral Angle Mapper (SAM) algorithm presented, unifying standard approach punctual XRF, information from mapped area database extend comprehension data outside region, working independently acquisition set-up. Experimental application some reference pigment layers painting Giotto presented validation proposed method.