## 3 Results and Discussions
### Dating the Label by Glycolysis Rate
The ancient varnish used for musical instruments, often applied over a thin film of finely divided plaster and dispersed in egg white solution in water, contains fine colophony powder dispersed in sicative oils (boiled flax, hemp, poppy, or walnut) in ratios ranging from 2:1 to 3:1 [30]. It is known that mixtures of sicative oils and diterpene resins (colophony derivatives), especially those of Pinaceae, were mostly used by [PERSON] for his violins [5; 6]. The main components of colophony are resinous monocarboxylic acids of alkyl hydro phenanthrene. These can be divided into two subgroups, namely pimaric and abiotic type acids [13]. The basic difference between the two groups is in the substituent at the C-13 position, which is isopropyl in abiotic acid and vinyl or methyl in pimaric acid [11; 13]. The varnishes used by [PERSON] have the ratio of 3:1 flax and colophony oil, with some dyes [6]. Figure 9: EDX spectra and elemental composition: (**a**) new varnish; (**b**) old varnish. The old recipe was made as follows [31; 32]: Pure linseed oil was heated to 270 \({}^{\circ}\)C, kept at this temperature for 3 h, and then cooled to 150 \({}^{\circ}\)C after which colophony was added; then this mixture was again heated to 250 \({}^{\circ}\)C for half an hour. The conservability of these varnishes over time is dependent on the nature and the ratio of the main constituents, but also on the presence of other additives [15; 16; 17; 18]. Being a hand-applied woodcutter film, the main causes of aging over time are contact with the acidic pH of the violinist's skin, the combined effect of welding moisture, skin lipids, and human temperatures, as well as exposure to light, especially to the UV spectrum [9; 29]. The chemical differences between the two varnishes existing on the violin (the old and the new varnish--subsequently applied) were studied using micro-FTIR spectroscopy, correlated with OM and SEM-EDX data, in order to determine the presence and the evolution of the different chemical components, respectively, and their state of preservation, in correlation with the period of re-varnishing after putting it into use. Varnish samples from the last application (new varnish) inside the layer showed a series of aggregates, perhaps particles, which could have come either from undispersed colophony or from additives, while the old varnish had such aggregates only on the surface or in the interface with the new varnish (applied later). The new varnish in the stratigraphic structure was dark yellow, with black aggregates on the surface, derived from colophony or oil entrained by photo-oxidation, and the second (the old varnish) was colorless, with fine aggregates of light brown colophony. As is known from the literature [33; 34; 35], when pure abietic acid is exposed to air, high temperature, or ultraviolet light, double-chromophore groups with a C=O connection disappear due to conjugation of \(\pi\)-\(\sigma\) (C-O). This phenomenon is due to the presence of colophony micro-aggregates, which induce a lower homogeneity of the thin film, with subsequent production of areas where the resin tends to become brown. Moreover, a large amount of undispersed colophony could stop the polymerization of the linseed oil film integrally through the cross-linking process, resulting in the presence of a non-homogeneous layer that is less resistant to natural aging factors. The chemical changes of the two varnishes, with different aging durations and causes, were evaluated from the micro-FTIR spectra for the two representative areas under study. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Assigned Functional Groups**} & \multicolumn{3}{c}{**Linseed Oil**} & \multicolumn{3}{c}{**Colophony**} \\ \cline{2-6}  & **Theor. ** & **New** & **Old** & **Theor.