# Micro-Raman Analysis of the Pigments on a Crucifix in Calabria
## 3 Results and Discussion  
Figure 2 shows photos of the six specimens investigated using Raman spectroscopy. For each specimen several points were analyzed, in order to provide detailed information on the pigments used. For instance, both samples S_4 and S_5, from the thong, appear green; however, the pigments found are not green, but yellow and blue. In general, a strong luminescent background is present in all the spectra. In some cases, it totally covers the Raman signal. By using the He-Ne laser for excitation, we obtain a better ratio of Raman signal over luminescence. However, we performed many measurements at different points on the samples in order to obtain a reasonable Raman-signal-to-noise ratio. Representative Raman spectra collected from the studies on different specimens are displayed in Figure 3.  
Because of the fine mixture of pigments present, in many cases, the spectral features originate from different materials. A summary of the various colors found in the Crucifix and studied via micro-Raman analysis is given in Table 1 below. Figure 2: Photographs of the six specimens of the Crucifix which were analyzed. Some of the collected spectra are shown in the following section. Various pigments were identified using the databases provided [5, 6, 7, 8, 9]. The first set of representative Raman spectra of the pigments found on the crucifix under examination is reported in Figure 3. Shown are pigments of ancient use, which are expected in a sculpture made in the XV century, after the most reasonable estimate. The Raman micro-analysis, however, also reveals the presence of other pigments, introduced in use more recently: besides the titanium white, discussed above, the spectra of some modern pigments are shown separately in Figure 3.  
First at all, we report, in Figure 3a, the spectrum of gypsum (calcium sulphate dihydrate), which was derived from the preparatory layer and was found in different samples, alone or in combination with other pigments. In addition, in the spectrum of gypsum, reported in Figure 3a, the presence of titanium white (anatase) is also revealed: in fact, the strong, low frequency peak at 143 cm\({}^{-1}\) is derived from it, as are the shoulders at 395 cm\({}^{-1}\) and 636 cm\({}^{-1}\), which overlap with the typical internal mode of the sulphates. In Figure 3b, the spectrum of hematite can be seen--called red ochre by painters--which was found in the red regions of our samples. This pigment, largely used, has been well known since prehistoric times for painting red and red-like zones. Another material used as a red color is cinnabar (mercury sulfide)--called vermillion in the artistic milieu--herein reported in Figure 3c, found in some regions of our samples. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Specimen Number** & **Origin of the Specim on the Sculpture** & **Color** \\ \hline S\_1 & Head of [PERSON] (upper side, hairs) & Brown \\ S\_2 & Face of [PERSON] (lower right side) & Carnation \\ S\_3 & Ribs (blood on the wound) & Red \\ S\_4 & Thong (upper zone, left side) & Green \\ S\_5 & Thong (lower zone, right side) & Green \\ S\_6 & Foot (blood on the wound) & Red \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Labels, and origin of the specimen on the sculpture and its dominant color. Figure 3: Representative Raman spectra collected on the specimen of Figure 2 with antique pigments: gypsum (**a**) hematite (**b**) vermillion (**c**) and carbon black (**d**). The Raman spectra shown in this picture were baseline-corrected. Finally, in the darker zones of this painted crucifix, carbon black was found, and its typical spectrum is reported in Figure 3d, corresponding to amorphous carbon. Some of the spectra associated with the modern pigments are reported in Figure 4.  
For instance, in the samples coming from the green zones of the sculpture, the occurrence of lithopone is revealed (see Figure 4a). In other measurements on the dark green regions, the spectrum of Prussian blue was collected.