## 3 Results and Discussion
### Characterizing the Color Appearance of Carpets under Different Illuminants
#### 3.1.3 Illuminant 02: Cool White Fluorescent (F02/10)  
Figure 7 charted the corresponding L*, a*, and b* values for different dyeing conditions considered in the methodology. Similar to the previous illuminants, recorded L*, a*, and b* values under F02/10 showed high conformity to the previous observations while addressing variations due to carpet features and gradual shading from light to darker shades. Hence, the inferences made in the previous sections are mostly applicable here while addressing the significant variances in L*, a*, and b* values caused by the carpet features and shade variations.  
Figure 6: Images of reflectance spectra [(43)].  
Figure 7: CIE L\({}^{\star}\), a\({}^{\star}\), and b\({}^{\star}\) values for F02/10 illumination of different carpets dyed in different shades of red and green colors (**a**) L\({}^{\star}\) values for red-colored carpets (**b**) L\({}^{\star}\) values for green-colored carpets (**c**) a\({}^{\star}\) values for red-colored carpets (**d**) a\({}^{\star}\) values for green-colored carpets (**e**) b\({}^{\star}\) values for red-colored carpets (**f**) b\({}^{\star}\) values for green-colored carpets.  
While comparing the resultant lightness-darkness (L*), redness-greenness (a*), and yellowness-blueness (b*) values for the same-colored carpet with the same shade under the three illuminants (D65/10 vs. A/10 vs. F02/10), significant variations have been observed. This is due to the energy level distribution (spectral power distribution) of the different color-associated wavelengths (spectral power distribution) of the incident and reflected light [44; 45]. For every illuminant, such energy distribution is distinguished. The correspondent wavelength of a definite color varies in radiant energy in the spectral power distribution for definite illuminants. Based on such varied energy distributions, the reflection, scattering, and absorption of the incident light by the colorant molecules will have different patterns for different illuminant types. As the energy distribution of the color-associated wavelengths for the reflected light is different for different illuminants, this will result in changes for the L*, a*, and b* values. Hence, the color perception will be different under different illuminants. This phenomenon can be realized from the images provided in Figure 8.  
From Figure 8 it can be seen that the images under A (incandescent) have darker appearance compared to the images under D65 (noon daylight) and F02 (cool white fluorescent). It is because the L values for A (incandescent) illuminant is lower than that of D65 (noon daylight) and F02 (cool white fluorescent). In addition, minor color differences can be perceived visually for dark shade whereas it is more evident in other two shades.  
Figure 8: Images of the carpet 1 under different illuminants. Image (**a**,**d**,**g**) refers to the views under D65 (noon daylight), images (**b**,**e**,**h**) refers to refers to the views under A (incandescent) and images (**c**,**f**,**i**) refers to refers to the views under F02 (cool white fluorescent) for a certain carpet with three different shades (picture resolution: 4032 \(\times\) 3024 pixels).