# Authentication of a Painting by [PERSON] Using Modern Multi-Analytical Methods
## 3 Results and Discussions
### Analysis of Painting Materials
The other elements (Ca, Ba, Zn, Fe, and Cr) for these samples come from impurities originating from other pigments and fillers from the preparation, induced in the elaboration of the painting on the easel or directly on the support, respectively, from the atmospheric dust (Si, Al, Mg, Ca, K, and Cl) incorporated during the display or storage period. For each color above, based on the percentage atomic composition and in correlation with the conservation state, a series of chemometric characteristics, with archaeometric value, were evaluated, given by the reports: Si/Al, C/O, C/S, S/O, Zn/O, Zn/C, and Zn/S. Further, a similar discussion was made for the three other pictorial materials: two colors of red (R1, R2) and one of yellow (Y), then one for the uncontaminated varnish (V) and one for the pressed cardboard support (S), without preparation. In the case of the first color of red (R1), besides the area with homogeneous color (sample R1.1), an area containing color and varnish fouled on the surface was taken (sample R1.2), from which the archaeometric characteristics were identified (diffusion between application layers and diffusion between pigments and the fouling structures). The same chemometric ratios were then evaluated as for the colors of blue. If sample R1.1 has an internal structure unaffected by environmental factors, with legible stratigraphy, easily distinguishable, sample R1.2 has a superficial structure with fouled varnish. The elemental composition of the two colors: both R1.1 and R1.2 contain _Ultramarine red_ pigment, mixed with _Siena_, _Iron red_ and _Zinc white/Lithopone_ and weakly impurified with chalk powder and gypsum, from preparation and cardboard, with the difference that R1.2 shows superficially areas with varnish fouling through oxidative processes. For the second color of red (R2), three representative color areas were selected with superficial fouled varnish, one with uniform distribution (sample R2.1) and two with non-uniform distributions (samples R2.2 and R2.3), easy to differentiate with OM/SEM. The elemental compositions also correspond to _Ultramarine red_ earth pigment, but differentiated: sample R2.1 contains _Ultramarine red_ pigment covered with uniformly fouled varnish, mixed with _Zinc white/Lithopone_ and weakly impurified with chalk powder and gypsum, from the preparation and cardboard, while the samples R2.2 and R2.3 have the same composition, but uneven fouling. In the case of the yellow pigment, only one sample (Y) was taken, in which the _Chrome yellow_ pigment (PbCrO\({}_{4}\)) and _Lithopone_ (zinc sulphide mixed with barium sulphate), diluted with other colors (_Ultramarine red_ and _Iron ocher_) were identified, and impurified with chalk powder and gypsum from the preparations, or with various contamination materials from the storage medium, having fouled varnish on the surface. In the case of the varnish sample (V), based on the elemental composition, it corresponds to a varnish based on natural resins, oxidatively fouled, with the incorporation of atmospheric dust. For the pressed cardboard support (S), similar to the varnish sample and the yellow one, only one sample was taken, and the SEM-EDX analysis was performed on the entire surface available for analysis. The elemental analysis corresponds to a cellulose material, impregnated with various leachable additives and filler material from the manufacturing processes and impurified by the materials in the missing layer. The results obtained by SEM-EDX analysis are correlated with those by \(\upmu\)-FTIR (Figure 17 and Table 2). Following the \(\upmu\)-FTIR analysis, the peak from 1730 cm\({}^{-1}\) attributed to the carbonyl group and the 2936, 2860, 1458, 1377, and 1174 cm\({}^{-1}\) peaks corresponding to the aliphatic groups were identified in all samples, highlighting the nature of the oil-based binder [10; 26; 27; 28; 31; 32; 33; 34].