The magnificent art of the inlay: study and materials characterization of Antonio Stradivari "Hellier" violin

Since the earliest periods of musical instrument making, the decoration of the violins with different techniques has had an important influence on the aesthetic characteristics and consequently the prestige and the worth of an instrument. Antonio Stradivari realized several stringed and plucked instruments decorated with various techniques: inlay, marquetry, wood etching and dying, similar to those used for furniture and precious wooden objects [1]. The Hellier violin (1679), actually held in Museo del Violino of Cremona (Italy), is one of the most important violin of this decorated stringed instruments. Figure 1 shows the lateral view of the Hellier violin with the ribs and head inlays. This research focuses on the study of the Hellier violin and on the analytical characterization of the materials, such as surface varnishes, inlays, purflings and decorations, with different totally not invasive diagnostic techniques. The UV-induced visible fluorescence, optical digital microscopy, ED-XRF associated with FTIR spectroscopy analysis, were performed. The investigations were aimed to identify the presence of original varnish layers, and to characterize the composition of the decorations, either the inlaid purflings or the black material used between them. The preliminary results suggest the presence of (i) oils with natural resins as main component of the varnishes, (ii) calcium phosphates (bone or ivory) in the white decorative elements of the inlays, and (iii) iron-gall ink in the black material of the top and back plate inlay and in the head and ribs decorations, as well as in the black strips of the purflings. Signals ascribable to the presence of the proteinaceous compounds were detected in the worn out areas of the violin