# Authentication of a Painting by [PERSON] Using Modern Multi-Analytical Methods
## 3 Results and Discussions
### Analysis of Painting Materials
The presence of the peak in the spectrum a (preparation layer) suggests that the artist used oil, along with binder based on animal glue, according to some recipes that are still used today. Therefore, the oil did not migrate from the paint layer. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Ion Type** & \begin{tabular}{c} **Expected Spectral** \\ **Bands (cm\({}^{-1}\))** \\ \end{tabular} & \begin{tabular}{c} **Peak Present in** \\ **Samples (cm\({}^{-1}\))** \\ \end{tabular} & **Samples Analyzed** \\ \hline Silicate & 860–1175 & 1174; 1124; 1088 & R \\ \hline Aluminate & 800–920 & 870 & R \\ \hline Sulphate and sulphide & 570–680; 960–1030 & 985 & B \\ \hline \multirow{4}{*}{Carbonate} & \multirow{4}{*}{670–745; 800–890; 1040–1100; 1320–1530} & 626 & W \\ \cline{2-3}  & & 1458 & S, V \\ \cline{2-3}  & & 1377; 1430; 1510 & R \\ \cline{2-3}  & 670–745; 800–890; 1040–1100; 1320–1530 & 724; 812; 1458; 1400 & B \\ \cline{2-3}  & & 724; 812; 870; 1400; 1458 & W \\ \hline \multirow{4}{*}{Phosphate} & 830–920; 1600–1900; 2150–2500; 2750–2900 & 2200 & B \\ \cline{2-3}  & & 2227 & W \\ \hline Pb (II, III, IV) & 660–685 & 669 & S, B \\ \hline \multirow{4}{*}{\
\begin{tabular}{c} Acvo-and \\ hidroxy-complexes, and \\ crystallized water \\ \end{tabular} } & 2850–4000 & 2860; 2936; 3388; & R \\ \cline{2-3}  & & 2860; 2936; 3388 & B \\ \cline{2-3}  & & 2860; 2936; 3388; 3429 & W \\ \hline \multirow{4}{*}{
\begin{tabular}{c} Binder (amide I and \\ amide II) \\ \end{tabular} } & \multirow{4}{*}{\(\approx\)1547; 1610–1690} & 1540 & V \\ \cline{2-3}  & & 1618; 1640 & W \\ \cline{1-1} \cline{2-3}  & & 1730 & S \\ \cline{1-1} \cline{2-3}  & & 1730; 1276 & V \\ \cline{1-1} \cline{2-3}  & & 1750 & 1276 & R \\ \cline{1-1} \cline{2-3}  & & 1730; 1276 & B \\ \cline{1-1} \cline{2-3}  & & 1730; 1276 & W \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Representative peaks and spectral bands of the ions identified in the samples analyzed by micro-FTIR. Figure 17: FT-IR spectrum for a series of samples analyzed by SEM-EDX: a—preparation layer (S), b—varnish (V), c—red (R), d—blue (B), e—yellow (Y), f—white (W). The bands characteristic of amide I and II with the peaks from 1640 and 1618 cm\({}^{-1}\) indicate the presence of protein binder based on animal glue. It is expected to have the presence of peak from 1550 cm\({}^{-1}\), which belongs to amide II in animal glue. It is shifted to 1540-1510 cm\({}^{-1}\), because the bone glue binder, obtained by hydrothermal processes, certainly affected the primary protein, which underwent degradation changes by chemically breaking down into oligo-peptides. Moreover, complexation interactions with transition metals in the composition of pigments have led to other composition changes. Additionally, the presence in small quantities of some mineral salts (Zn, Pb, Ca, etc.) in the form of carboxylate (metal soaps), proves that the painter masters the artistic technique. The preparation layer (Figure 17a) shows the peaks: 3429, 2936, 2860, 1730, 1618, 1458, and 669 cm\({}^{-1}\) characteristic of the binder based on animal glue and carbonate. The varnish (Figure 17b) shows the peaks 3532, 2936, 2860, 1730, 1540, 1458, 1276, 1174, and 1088 cm\({}^{-1}\) characteristic of boiled linseed oil-based binder [10; 26; 27; 28; 29; 30]. The red pigment (Figure 17c) shows the peaks 3388, 2936, 2134, 1618, 1510, 1430, 1377, 1276, 1174, 1124, 1088, and 870 cm\({}^{-1}\) characteristic of the binder and the mixture of _Ultramarine red, Sienna and Iron red_, from the elaboration on the easel, together with white from calcium and barium carbonate impurified in the technology of manufacturing the oil color. The blue pigment (Figure 17d) shows the peaks 3388, 2936, 2860, 2516, 2200, 2055, 1964, 1730, 1618, 1458, 1400, 1314, 1276, 985, 812, 724, 669 cm\({}^{-1}\) characteristic of the binder, _Ultramarine blue and Zinc white_[10; 26; 27; 28; 31; 32; 33; 34; 35].