## 4 Discussion
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Wall Paintings** & **Pigments** & **Organic Materials** & **Fillers/Extenders** \\ \hline \multirow{8}{*}{_Trinity_} & Zinc white, & Animal glue & \\  & Cadmium yellow, & Casein & \\  & Cadmium/mercury orange, & & \\  & Vermilion, & & \\  & Red/brown/black earths, & & \\  & Organic red pigment, & & \\  & Chrome-based greens, & & \\  & Ultramarine blue, & & \\  & Ivory black & copolymer \({}^{\star}\) & \\ \hline \multirow{8}{*}{_Eucharist_} & Sangiovanni white, & & \\  & Cadmium yellow, & & \\  & Yellow/red ochre, & & \\  & Vermilion, & & \\  & Chrome-based greens, & & \\  & Green/brown/black earths, & & \\  & Cobalt blue, & & \\  & Ivory black & & \\ \hline \multirow{8}{*}{_St. Nicolas_} & Sangiovanni white, & & \\  & Cadmium yellow, & & \\  & Yellow/red ochre, & & \\  & Chrome-based greens, & & \\  & Green/brown/black earths, & & \\  & Ultramarine blue, & & \\  & Cobalt blue & & \\ \hline \multirow{8}{*}{_St. Sebastian_} & Sangiovanni white, & & \\  & Cadmium yellow, & & \\  & Yellow/red ochre, & & \\  & Chrome-based greens, & & \\  & Green/brown/black earths, & & \\  & Ultramarine blue, & & \\  & Cobalt blue & & \\ \hline \multirow{8}{*}{_Virgin and Child_} & Sangiovanni white, & & \\  & Cadmium yellow, & & \\  & Yellow/red ochre, & & \\  & Vermilion & & \\  & (only in _Virgin and Child_), & & \\  & Chrome-based greens, & & \\  & Holy family & Green/brown/black earths, & & \\  & Ultramarine blue, & & \\  & Cobalt blue, & & \\  & Ivory black & & \\  & Possible alizarine lake & & \\  & (only in _Holy family_) & & \\ \hline \hline \end{tabular} \({}^{\star}\) non-original added materials.  
\end{table} 
Table 2: Summary of the analytical results obtained from the study of Semsales wall paintings. For the other figurative wall paintings (_Eucharist_, _[PERSON]_, _[PERSON]_, _Virgin and Child_ and _Holy family_), [PERSON] used the traditional _a fresco_ and lime-based technique experimented for the first time only a few years earlier in the castle of Montegufoni in Tuscany (1921-1922) [30]. The non-invasive infrared analyses supported and integrated by the study of the cross-sections proved the use of lime as binder. However, the detection of oxalates and weak carbonyl and CH bands indicate a possible addition of small amounts of organic material. The range of pigments identified in the Semsales murals reveals that [PERSON] combined traditional _a fresco_ pigments (e.g., iron-based pigments) with modern ones, i.e., zinc white (only in the _Trinity_), cobalt blue, synthetic ultramarine blue, synthetic alizarin lake, chrome-based greens and cadmium-based yellow and orange pigments (see Table 2 for the complete list). In particular, the cadmium-based pigments are readily identified by technical photography thanks to their characteristic luminescence revealed in both UVL and VIL images [31]. Analytically, the use of modern pigments in the 20 th century has been widely explored in easel paintings [32; 33; 34; 35; 36], while their application in wall paintings is less known [37; 38; 39]. In addition, Semsales is an exceptional example of extensive use of cadmium-based pigments not commonly found in wall paintings, especially the cadmium/mercury sulphide type [40] that probably corresponds to the cadmium orange purchased for the church decoration (see Table S1). The analytical data are generally in accordance with the results of the archival research. For example, the pigments identified and the casein are listed in the invoices of materials purchased for the church decoration (see Table S1). However, there are some incongruences, and some questions remain open. Notably, the use of potassium silicate, listed among the materials purchased for the decoration of the church and mentioned by [PERSON] in his writings for the silicate paint [41], was not analytically identified with the methods used in any of the wall paintings studied.