## 3 Results
### Reflectance Values at a Wavelength of 1000-1700 nm  
Table 11 presents selected descriptive statistics of the reflectance at a wavelength of 1000-1700 nm. \begin{table}
\begin{tabular}{c c c c} \hline \multicolumn{4}{c}{**Oil A: Conover–Iman post hoc test; \(p\) =**} \\ \hline
**Intertemporal comparison** & **A\_0** & **A\_20\_min** & **A\_60\_min** & **A\_120\_min** \\ \hline
**A\_0** & & 0.8981 & 0.1282 & 0.0629 \\ \hline
**A\_20\_min** & 0.8981 & 0.0999 & 0.0542 \\ \hline
**A\_60\_min** & 0.1282 & 0.0999 & 0.5226 \\ \hline
**A\_120\_min** & 0.0629 & 0.0542 & 0.5226 \\ \hline \multicolumn{4}{c}{**Oil B: Conover–Iman post hoc test; \(p\) =**} \\ \hline
**Intertemporal comparison** & **B\_0** & **B\_20\_min** & **B\_60\_min** & **B\_120\_min** \\ \hline
**B\_0** & & 0.0530 & 0.6735 & 0.0096 \\ \hline
**B\_20\_min** & 0.0530 & 0.0197 & 0.0000 \\ \hline
**B\_60\_min** & 0.6735 & 0.0197 & 0.0277 \\ \hline
**B\_120\_min** & 0.0096 & 0.0000 & 0.0277 \\ \hline \multicolumn{4}{c}{**Oil C: Conover–Iman post hoc test; \(p\) =**} \\ \hline
**Intertemporal comparison** & **C\_0** & **C\_20\_min** & **C\_60\_min** & **C\_120\_min** \\ \hline
**C\_0** & & 0.3496 & 0.1114 & 0.0131 \\ \hline
**C\_20\_min** & 0.3496 & 0.0131 & 0.0009 \\ \hline
**C\_60\_min** & 0.1114 & 0.0131 & 0.03496 \\ \hline
**C\_120\_min** & 0.0131 & 0.0009 & 0.3496 \\ \hline
**Oil D: Conover–Iman post hoc test; \(p\) =**} \\ \hline
**Intertemporal comparison** & **D\_0** & **D\_20\_min** & **D\_60\_min** & **D\_120\_min** \\ \hline
**D\_0** & & 0.7045 & 0.4491 & 0.0350 \\ \hline
**D\_20\_min** & 0.7045 & 0.2577 & 0.0138 \\ \hline
**D\_60\_min** & 0.4491 & 0.2577 & 0.1677 \\ \hline
**D\_120\_min** & 0.0350 & 0.0138 & 0.1677 \\ \hline \end{tabular}
\end{table} 
Table 10: Results of post hoc tests of the reflectance at a wavelength of 700–1100 nm after the application of Oils A, B, C, and D.  
In the assessment of differences in reflectance values at subsequent time points (before oil application, after 20 min, and after 60 min) a statistically significant difference (\(p\) = 0.0093) was found between particular time points for the reflectance at a wavelength of 1000-1700 nm after the application of Oil A. It was found that at a wavelength of 1000-1700 nm after the application of Oil A (Table 12), the reflectance value after 20 min of exposure was statistically significantly lower compared with the value before exposure, and the reflectance values after 60 min and 120 min of exposure were statistically significantly higher compared with the value after 20 min of exposure. In the assessment of differences in reflectance values at subsequent time points (before oil application, after 20 min, and after 60 min), a statistically significant difference (\(p\) < 0.0001) was found between particular time points for the reflectance at a wavelength of 1000-1700 nm after the application of Oil B. It was found that at a wavelength of 1000-1700 nm after the application of Oil B (Table 12), the reflectance value after 20 min of exposure was statistically significantly lower compared with the values before exposure and after 60 min and 120 min of exposure. Also, the reflectance value after 60 min of exposure was statistically significantly higher compared with the value before exposure and statistically significantly lower compared with the value after 120 min of exposure.