## 3 Results
### Morphological Characterization of Contaminated Mural Paintings
The luminosity, red-green and yellow-blue coordinates of each inoculated area were recorded and, based on them, the \(\Delta E\) value were calculated (Figure 6) in order to highlight the differences between areas prior to the application of consolidants and after various treatments had been applied. The calculated \(\Delta E\) values are shown in (Table S1), where \(\Delta E_{0}^{*}\) represents the difference between the samples with and without consolidants and \(\Delta E_{n}^{*}\) (1-6) represents the difference between the reference and inoculated areas. In the case of the sample covered with TDC, all \(\Delta E_{n}^{*}\) values were greater than the \(\Delta E_{0}^{*}\) values, which means that, from the colourimetric point of view, there were greater changes induced between the inoculated areas and the reference areas than between the reference areas with and without consolidants. All areas showed colour changes that were perceptible with close observations, with \(\Delta E^{*}\) values between 1 and 2 (Table S1). The lowest \(a^{*}\) values were measured for the area inoculated with _Bipolaris_ sp. M3 on red pigment and for the areas inoculated with _Bipolaris_ sp. M4 and M7 on green pigment. The removal efficiency calculated from the colourimetry data (Table S2) showed very high negative values for all inoculated areas. Figure 4: Growth of fungal strains on painted experimental models covered with Paraloid® B72 and TDC. Abbreviations: R (red), Y (yellow), B (blue), G (green). Experimental models without consolidants were used as a control. Most of the \(\Delta E^{*}\) values calculated for the Paraloid(r) B72-covered sample (Figure 7) were between 1 and 2, which indicated colour changes perceptible through close observation. The lowest values were calculated for the _Aspergillus_ sp. S1 and _Bipolaris_ sp. M4 strains applied on yellow pigment, for the _Bipolaris_ sp. P2, M4 and M7 strains applied on red pigment and for the _Bipolaris_ sp. M3 strain applied on green pigment. These values were the closest to the reference, which may be an indication of the role of fungi in the decomposition of Paraloid(r) B72. At the opposite end, the highest differences were calculated for _Aspergillus_ sp. S1 and _Bipolaris_ sp. M3 applied on the blue and red pigments and for _Bipolaris_ sp. M3 and _Ullocadium_ sp. H1 applied on the yellow pigment. Figure 5: The growth of fungi on the painted experimental models covered with TDC. (**a**,**d**,**g**,**j**) _Aspergillus_ sp. S1; (**b**,**e**,**h**,**k**) _Bipolaris_ sp. M7; (**c**,**f**,**i**,**i**,**i**) control. Although all treated areas had higher luminosity values compared to the reference for the samples covered with Paraloid(r) B72, much higher \(L^{\star}\) values for the red and blue pigments could be seen in areas where _Aspergillus_ sp. S1 and _Bipolaris_ sp. M3 were inoculated. This correlated with the lowest \(a^{\star}\) values for the red pigment and higher \(a^{\star}\) values for the green pigment, which may have indicated colour changes in comparison to the other areas. Similarly, the lowest \(b^{\star}\) value was recorded for the area inoculated with _Ullocalium_ sp. H1 on the yellow pigment, while the highest \(b^{\star}\) value was seen for the area inoculated with _Bipolaris_ sp. P2 on the blue pigment. For both TDC and Paraloid(r) B72, \(a^{\star}\) values were lower than the reference for the red pigment, while \(b^{\star}\) values were mostly all higher than the reference for the green pigment, with the exception of the area treated with _Bipolaris_ sp. P2. Similarly, for the blue pigment, \(b^{\star}\) values were all higher compared to the reference. Likewise, for the TDC-covered sample, the calculated removal efficiency for the treatments applied to the Paraloid(r) B72-covered sample (Table S2) indicated very high negative values. However, some exceptions were seen in three areas that were treated with _Bipolaris_ sp. M3 (on yellow and red pigment) and _Bipolaris_ sp.