## 3 Results and Discussion
### Analysis of Moratars by Means of SEM/EDS  
The samples, BB7 and BB8, from mortars were studied via microscopic examination of the cross sections (see Figure 3a,d). The elemental composition of samples was examined by SEM/EDS. It has been observed that the particle size of the inert has a diameter of about 125 um to 1 mm, as is evident in Figure 3a,c. It can be defined as medium-coarse, sub rounded. The inert-binder ratio, also called thickening, is believed to be around 40-50%. The adhesion of the grain/binder does not seem very good, since cracks can be observed around the grains. About the composition of the inert, from the analyses by EDS (Figure 3b,d), carbonates and quartz can be observed. As for the chemical composition, the mortar would be compatible with a weakly hydraulic lime, but given that it crumbles easily, it is very likely that it is an aerial lime obtained from a calcium-carbonate-containing clay. With regard to the paint layer, thicknesses of about 10 um were observed for the BB7 sample, (Figure 3b), the same thickness as the BB8 sample, with some grains containing barium (Figure 3d). The results are reported in Table 3.  
Characterization of the Organic Binders by Means of Micro-FT-IR Spectroscopy and GC/MS 3.3.1. Micro-FT-IR Spectroscopy Measurements  
The wall painting samples, BB3 (dark green), BB4 (gray), BB5 (red), and BB6 (gray-violet) were preliminarily analyzed by FTIR spectroscopy, in order to verify the presence of organic binders. By means of FTIR measurements, features of both inorganic and organic materials were detected. In all samples analyzed, calcium sulphate (CaSO4) and calcium carbonate (CaCO3) were present, recognizable by the characteristic vibration bands at 3537, 3407, 1683, 1620, 1106, 671, and 598 cm\({}^{-1}\)[32; 47], for gypsum and at 1428, 875, and 712 cm\({}^{-1}\) for calcium carbonate [48; 49]. In the samples, BB4 and BB6, barium sulphate was found, as  
Figure 3: SEM- images in BSE of the cross-section of BB7 (a) and BB8 (c) samples; EDS analysis collected on the areas 1 and 4 of the BB7 (b) and BB8 (d) samples. reported by Raman measurements as well. In BB5, in addition to the characteristic features of haematite (Fe\({}_{2}\)O\({}_{3}\)) at 568 and 478 cm\({}^{-1}\), the vibrational absorption of quartz (SiO\({}_{2}\)), usually occuring in red ochre mixed with haematite, at 797, 781, and 693 cm\({}^{-1}\)[49; 50], was also detected. In the FTIR spectrum of BB6, the bands at about 1015 and 930 cm\({}^{-1}\), associated with the blue ultramarine blue pigment (Na\({}_{7}\)Ca(Al\({}_{6}\)Si\({}_{6}\)O\({}_{24}\))), were found [51], in agreement with Raman results. The features ascribed to proteinaceous materials (probably a mixture of egg and animal glue) are clearly visible in all samples: the symmetric and antisymmetric stretching vibrations of CH\({}_{2}\) and CH\({}_{3}\) in the 2952-2848 cm\({}^{-1}\) range; the carbonyl stretching vibration at 1731 cm\({}^{-1}\), identificative of egg; amide I at 1643 cm\({}^{-1}\) (egg) and 1619 cm\({}^{-1}\) (animal glue); and amide II at 1540 cm\({}^{-1}\), due to the proteic fraction. In addition to proteinaceous material, polysaccharides were also found: at 3320 cm\({}^{-1}\), the stretching vibration of OH groups and at 1020 cm\({}^{-1}\), the stretching vibration of the C-O-C glycosidic bond. The use of polysaccharides as binder, in particular, arabic gum, is frequently reported in \"illuminated\" manuscripts but rarely reported in wall paintings [52; 53]. In the BB3 sample, beeswax was identified by the typical doublets at 2916 and 2848 cm\({}^{-1}\), at 1472 and 1462 cm\({}^{-1}\), and at 730 and 718 cm\({}^{-1}\), due to methylene groups stretching and in plane and out of plane bending vibrations, respectively [32; 54].