Non-invasive Examination of Stratigraphic System in violins: the thickNESS project

In this project, Optical Coherence Tomography (OCT) and Nuclear Magnetic Resonance (NMR-MOUSE) have been applied to precious historical violins made by Amati, Stradivari and Guarneri, and hosted in the Museum of Violin in Cremona, as well as to large fragments removed during past restorations from ancient bowed string instruments. OCT study was carried out with a prototype high-resolution portable SdOCT instrument [1] providing layer thickness measurements and information about the presence of particles, cracks and delaminations. NMR analyses were performed with a Magritek Kea spectrometer and a Profile NMR-MOUSE (PM5) [2] giving information on the wood density and elasticity, the last one possibly related to adopted treatments. Since the analytical campaign finished in October 2018, data interpretation is still in progress and promising results are expected to reveal in-depth insight into the finishing violin making process. These data will be integrated with the results from UVIFL, FT-IR, Raman and XRF techniques in order to set up a methodology which allowed researchers to non-invasively characterize the stratigraphy of historical violins.