## 3 Results
### Inks Samples from the Main Hall  
Regarding the sampled inks from the main hall, the analysis by XRF was more complicated due to the effect of the environment, as can be seen in Table 3. In the first layers, it was possible to observe as major elements sulphur and calcium, the relative concentration of which decreased with the depth. In fact, sulphur in the inner layers appeared as a minor element. This was due to the action of atmospheric acid gases that have considerably affected the building [23; 24]. In this sense, it is remarkable that the inks acted as a protective layer, minimizing the impact of the atmospheric SO\({}_{2}\) on the original material, the result of wet or dry deposition due to the marine aerosol and usual fogs in the area, in contrast to the supposed increase of the degradation that these inks generate in the original materials [6]. This protection most likely will be the consequence of the high number of ink layers. Leaving aside this effect, elements such as silicon and potassium could be also related to the particulate matter, due to the marine aerosol and sand from the near beach [1; 18; 24]. Taking all of these in consideration, titanium again seems to be a relevant element in the spray's compositions. However, once again, rutile was observed by Raman spectroscopy only when it was used as pigment and not when used as additive, possibly due to the quantity present [16]. The study of each ink allowed its identification (Figure 5 and Table 4); starting from the external layer, the T1 ink presented lead in the elemental analysis, and by Raman spectroscopy, lead moldybdate chromate pigment (PR104) was found, as can be seen in Figure 5[15]. This pigment was composed of lead chromate, moldybdate and sulphate (PbCrO\({}_{4}\)PbMoO\({}_{4}\)PbSO\({}_{4}\)) [25]. The next two inks, T2 and T3, were identified as acetoacetic arylide (PY74), also observed in the measured commercial sprays. Even so, the T3 pigment was mixed with iron hydroxide, goethite, as it was assumed in view of the presence of iron in the elemental analysis [16]. This mixture possibly was formulated to obtain the desired tone. Following the layers, the next layer, T4, was identified as copper phthalocyanine (PB15), also identified in the commercial inks, although in this case copper was not found in the elemental analysis [15]. The T5 ink was clearly differentiated, since it was a light orange colour, and was identified as a mixture of two pigments, disazo pyrazolone PO34 and the previously mentioned PY74 [15]. Deeper, the T6 layer, again with a blue colour, showed the PB15 pigment, and in this measurement, copper was identified, as expected [15]. The next three layers (T7-T9) seemed to be very related. In the T7 layer, rutile was identified as a white pigment, along with the alkyld binder observed in the commercial sprays. The next colour was \"Bone White\" and was considered as a different layer, and in this case titanium oxide, rutile, as white pigment, PY74 as yellow pigment, and a weak band at 1003 cm\({}^{-1}\), which could be related to the binder, were identified [15; 16]. The differences between both inks were clear, however; the T9 was an ochre colour, and was identified as PY74 and iron oxide, goethite, confirmed by the major presence of iron in the elemental analysis [15; 16]. So, the T8 layer could be a mixture of the other two layers (T7 and T9). Regarding the elemental analysis, there were some differences, but not enough to confirm if it was a different layer. Continuing, as in the case of commercial sprays, the green colour T10 seemed to be phthalocyanine due to the presence of copper and chloride in the elemental analysis. This observation was confirmed by Raman spectroscopy, which identified PG7 pigment, the copper-based phthalocyanine also observed in the commercial sprays [15]. This pigment also was identified in the final, inner layer, T12. However, the elemental analysis did not help in this case. Finally, the remaining ink, T11, was identified as PR48 or PR48:2 [15].