# Comparative Studies on Nanocellulose as a Bio-Based Consolidating Agent for Ancient Wood
## 3 Results and Discussion
### Characterization of Treated Degraded Wood Samples
In fact, although it was not easy to observe the presence of the different products (CNC (A), Paraloid B-72 (B) and Regalrez 1126 (C)) in these visible light images, it is interesting to see how only the sample treated with CNC turned out to be very similar to the untreated sample in terms of color; on the contrary, the samples treated with Paraloid B-72 and Regalrez 1126 were darker than before the application. All the colorimetric data collected from the treated wood samples are shown below. Comparing the colorimetric data of the untreated sample with those of the treated samples collected a few days after the first treatment (Tables 2-4), it can be observed that the difference in brightness on the L* axis (\(\Delta\)L) for the CNC-treated samples was much lower than the \(\Delta\)L of the Paraloid B-72 and Regalrez 1126-treated samples; this means that the CNC did not change the original brightness of the wood. The same consideration can be made for the parameter \(\Delta\)C, which concerns color saturation. For the most important parameter \(\Delta\)E, which is the total color difference, this becomes a significant piece of data when it is greater than five; in this case study, while for the CNC it was less than one, for the other two consolidating products it was greater than 13, demonstrating that the color of the samples treated with Paraloid B-72 and Regalrez 1126 varied greatly compared to the untreated sample. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & **L* (D65)** & **a* (D65)** & **b* (D65)** & & & & \\ \hline \multirow{3}{*}{**NT**} & SCI & 64.82 & 9.30 & 24.03 & & \(\Delta\)L & \(\Delta\)C & \(\Delta\)E \\ \cline{2-8}  & SCE & 64.71 & 9.34 & 24.12 & SCI & \(-\)0.84 & 0.32 & 0.90 \\ \hline \multirow{2}{*}{**Nanocellulose**} & SCI & 63.98 & 9.04 & 24.21 & SCE & \(-\)0.85 & 0.33 & 0.91 \\ \cline{2-8}  & SCE & 63.86 & 9.08 & 24.32 & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of the colorimetric parameters (L*, a*, b*) of the untreated sample (NT) and the samples treated with nanocellulose. Figure 5: Reflected light microscope images of samples that were not-treated (NT) and those treated with CNC (A), Paraloid B-72 (B), and Regalrez 1126 (C). Images with UV light and 5\(\times\) magnification (**a**,\(c\),**e**,**g**); images with visible light and 2.5\(\times\) magnification (**b**,\(d\),\(f\),**h**). White arrows indicate in all samples the signs of degradation due to the action of xylophagous insects. The graph in Figure 6 shows the percentage reflectance values, obtained as a function of the incident wavelength for all the treated and untreated samples, acquired in the SCI and SCE mode, confirming what has just been reported above and demonstrating that the samples treated with CNC were lighter than those treated with Paraloid B-72 and Regalrez 1126, which darkened after treatment. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & \multicolumn{2}{c}{**L\({}^{*}\) (D65)**} & \multicolumn{2}{c}{**a\({}^{*}\) (D65)**} & \multicolumn{2}{c}{**b\({}^{*}\) (D65)**} & & & \\ \hline \multirow{2}{*}{**NT**} & SCI & 64.82 & 9.30 & 24.03 & \(\Delta\)L & \(\Delta\)C & \(\Delta\)E \\ \cline{2-8}  & SCE & 64.71 & 9.34 & 24.12 & SCI & \(-\)13.58 & 6.68 & 15.14 \\ \hline \multirow{2}{*}{** Paraloid B72 TR**} & SCI & 51.24 & 14.07 & 28.71 & SCE & \(-\)13.74 & 6.81 & 15.34 \\ \cline{2-8}  & SCE & 50.97 & 14.17 & 28.92 & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of the colorimetric parameters (L\({}^{*}\), a\({}^{*}\), b\({}^{*}\)) of the untreated sample (NT) and the samples treated with Regalrez 1126.