## 3 Results and Discussion
### Pigments
#### 3.2.1 Green  
At least two different past restorations are evident on the bases of the detected green pigments, where one was characterized by the use of a copper-based pigment and the other by a chromium-based green. Indeed, copper-based green and green earth were detected, either coupled in the same measured point or separated in different points (see Table 1 for details). This could possibly be linked to various restoration phases and can be related to imaging mapping [17]. For instance, in panel D, both copper-based green and green earth (this last supposed was to be the original material for greens) were detected together with high zinc signals in the XRF spectra, indicating a modern intervention, while in one detail on panel A, only copper-based green was found together with high signals of zinc,  
\begin{table}
\begin{tabular}{c|c|c} \hline
**Panel** & **Color** & **Pigments** \\ \hline Panel A, E & Green & Green earth with small quantities of a copper-based pigment \\ \hline Panel A & Green & Green earth with zinc white with small quantities of chromium-based pigment \\ \hline Panel A & Green & Green earth, zinc, and lead white, chromium-based pigment with small \\ \hline Panel A & Green & quantities of copper-based pigment \\ \hline Panel E & Green & Green earth and other iron oxides \\ \hline Panel A & Green & Copper-based pigment with lead white \\ \hline Panel D & Green & Copper-based pigment, green earth, and zinc white \\ \hline Panel E & Green & Copper-based pigment with green earth and zinc white \\ \hline Panel A, D, E & Flesh tones & Iron oxides \\ \hline Panel A & Flesh tones & Iron oxides with zinc and lead white \\ \hline Panel A, E & Blue & Azurite \\ \hline Panel A & Blue & Ultrararine with zinc and lead white \\ \hline Panel D & Blue & Ultrararine with zinc white \\ \hline Panel A & Blue & Prussian blue with zinc white \\ \hline Panel A, D & Red & Iron oxides \\ \hline Panel A, E & Red & Iron oxides with small quantities of vermillion \\ \hline Panel E & Red & Vermillion \\ \hline Panel A, D, E & Yellow & Yellow ochre \\ \hline Panel D & Yellow & Yellow ochre and zinc white \\ \hline Panel E & Yellow & Yellow ochre with small quantities of vermillion \\ \hline Panel E & Brown & Iron oxides \\ \hline Panel A, D, E & White & Calcite \\ \hline Panel A & White & Calcite with small quantities of zinc white \\ \hline Panel D & Black & Carbon or bone black \\ \hline \end{tabular}
\end{table}
Table 1: Summary table of the pigment detected in the different investigated areas on panels A, D, and E.  
Figure 2: Digital optical microscope images: on the (**left**), panel A, dark red vest (ochre with vermillion); on the (**right**), panel A, flesh tone, restored area (ochres, lead white, and zinc white). Red scale bars correspond to 0.2 mm.  
indicating this pigment was surely used for restoration intervention. On the other hand, in the restored green areas of panel A, characterized by a high zinc presence, significant chromium signals were detected through XRF analysis. From the in situ noninvasive investigations, the green points left several open questions; for this reason, the green areas were chosen for sampling and laboratory analyses [21].