# New Insights on the [PERSON] \"Coristo\" Mandolin: A Combined Non-Invasive Spectroscopic Approach  
[PERSON]  
1 Arved Laboratory of Non-Invasive Diagnostics, CISRIC, University of Pavia, Via bell'Aspa 3, 26100 Cremona, Italy; [EMAIL_ADDRESS] (F.V.); [EMAIL_ADDRESS] (G.F.); [PERSON](T.R.); [PERSON].L.); [PERSON]S] (M.A.)  
[PERSON]  
1 Arved Laboratory of Non-Invasive Diagnostics, CISRIC, University of Pavia, Via bell'Aspa 3, 26100 Cremona, Italy; [EMAIL_ADDRESS] (F.V.); [PERSON]] (G.F.); [PERSON](T.R.); [PERSON].L.); [PERSON]S] (M.A.)  
[PERSON]  
1 Arved Laboratory of Non-Invasive Diagnostics, CISRIC, University of Pavia, Via bell'Aspa 3, 26100 Cremona, Italy; [EMAIL_ADDRESS] (F.V.); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (T.R.); [EMAIL_ADDRESS] (C.L.); [EMAIL_ADDRESS] (M.A.)  
[PERSON]  
1 Arved Laboratory of Non-Invasive Diagnostics, CISRIC, University of Pavia, Via bell'Aspa 3, 26100 Cremona, Italy; [EMAIL_ADDRESS] (F.V.); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (T.R.); [EMAIL_ADDRESS] (C.L.); [PERSON]S] (M.A.)  
[PERSON]  
3 Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy; [EMAIL_ADDRESS] (Correspondence: [EMAIL_ADDRESS] (Correspondence: marco.  
and increase the rate of drying of the varnish [12]. Under the varnish, a ground layer was often detected and described as a mixture of protein-based materials with a dispersion of inorganic fillers, such as silicates or sulfates [13]. Moreover, the presence of a pre-treatment of the wood has been suggested by several authors, although it was barely detected and identified [14; 15; 16].  
The contribution of [PERSON] to instrument making is not only limited to bowed string instruments, i.e., violin, viola, and cello, but also includes plucked string instruments such as guitars, lutes, harps, and mandolins. His wide production is confirmed by tens of drawings and molds of different kinds of musical instruments currently conserved in the Museo del Violino in Cremona, Italy [3]. Among the plucked string instruments of [PERSON], only two mandolins are known to have survived: the oldest, named \"The Cutler-Callen\", made in 1680 and conserved in the National Music Museum in Vermillion, South Dakota, USA [16]; and the \"Coristo\" mandolin that was made between 1700 and 1710, currently conserved in the Museo del Violino in Cremona (Figure 1; high-resolution images are reported in Figures S1-S6 in Supplementary Information). The latter extraordinary example of the [PERSON] musical instrument is the object of this study.  
From historical sources, we know that the mandolin probably derived from an ancient Arab instrument similar to a small lute, and it succeeded in Italy principally over the 17 th and 18 th centuries due to an important production of music made on purpose for this type of instrument [17; 18]. Concerning the materials used to finish a mandolin, though, little information is available [19]. In this view, for the first time, the analytical results on the \"Coristo\" mandolin made by [PERSON] are here presented, using a combined approach of three non-invasive techniques: UV-induced fluorescence imaging, reflection Fourier transformed infrared (FT-IR) spectroscopy, and X-ray fluorescence (XRF). These complementary techniques were selected based on the capability of UV, IR, and X-ray radiations to obtain information from different organic and inorganic materials, allowing us to non-invasively characterize the coating system. The goals of the study were to: (i) identify the materials used by [PERSON] in the finishing processes of the mandolin, (ii) compare these materials with those used in violin finishing, and (iii) increase the knowledge of materials and techniques applied by the Master in the less-explored class of plucked string instruments.  
Figure 1: Images in visible light (**a–c**), and UV-induced fluorescence (**d–f**) of the front, the back, and the right treble side of the “Coristo” mandolin.