A multidisciplinary materials characterization of a Joannes

Background: Several musical instruments in the past centuries were decorated with engravings, inlays, or paintings. This paper focuses on an integrated approach to detect and characterize the kind of dyes when used for the decorations. The multi analytical campaign was performed on a viol made by Joannes Marcus in the second half of the 16 century. The instrument has been shattered during World War II, and the fragments are now held in Conservatorio Giuseppe Verdi in Milan; they still conserve the original black and white purflings and the painted decorations. The study is of critical importance since Joannes Marcus worked in the sixteenth century and, in this very period, some executive features were introduced in musical instrument making, which are now veritable standards for this kind of instruments. Results: At first, UV fluorescence examination and reflectographic analysis have been performed on the different fragments in order to characterize, respectively, the distribution of varnishes and glues on the surface and to select the areas treated with metal-gall inks that result transparent by long wave IR reflectographic technique. The materials were therefore characterized with X-Ray Fluorescence (EDXRF), Scanning Electron Microscopy with Energy dispersive X-Ray spectroscopy (SEM-EDX) microanalyses and Micro-Infrared Spectroscopy (μFT-IR) techniques. In particular, the metallic elements present in the dyes where revealed through XRF and SEM-EDX, while μFT-IR gave details about organic binders. Elemental compositions obtained for the black decorations allowed to distinguish original parts of the fragments from those restored or remade. Conclusions: The characterization of materials performed by our multi analytical approach, allowed us to get a deep knowledge of the technology of this ancient viol maker. In particular, the varnishes are probably composed by a diterpenic and/or triterpenic resin. In the same way, in a few traces of glue the presence of proteinaceous substances have been individuated. As for the brush-decorated area, they present a preparation layer rich in feldspars on which a black layer of carbon black particles is applied. On the other hand the purfling areas are colored by an iron-gall dye. In particular the usage of a different ink allowed to identify restored areas.