A non-invasive stratigraphic study by reflection FT-IR spectroscopy and UV-induced fluorescence technique: The case of historical violins

In the present work, a novel non-destructive and non-invasive methodology combined UV-Induced Fluorescence (UVIFL) photography and reflection FT-IR spectroscopy to investigate how and to what extent varnish thicknesses vary on the surface of historical violins as well as to reconstruct the stratigraphic layer order and chemical composition. Firstly, UV-induced variations and IR diagnostic bands were identified on numerous model samples reproducing musical instrument stratigraphy. Then the methodology was applied to the study of several Stradivari and Guarneri violins and its limitations and strengths were showed in three representative case studies.