Computing characteristics of color difference formulas for regular coordinate changes in CIELAB color space

Because of the non-uniformity of the CIELAB color space, scientists and researchers have tried to find the best formula for the CIELAB color space which provides consistent color difference results. The computing performances of the four color difference formulas (CIELAB1976, CMC, CIE94, and CIEDE2000) were tested in the four principal hue regions of the CIELAB color space at a constant lightness value of 50 ( L* = 50) which corresponds to the largest chromaticity plane around the gray point ( L* = 50; a* = 0; b* = 0). The dependence and consistency of the four formulas were investigated according to regular and constant color coordinate changes by using a specially prepared computer software. The experimental results showed that the three formulas other than CIELAB1976 computed in different manners peculiar to themselves and the CMC formula gave the most distinct results on different hue regions of the a *– b * color plane. CIELAB1976, CIE94, and CIEDE2000 formulas were found to compute the most consistent color difference results in the different hue regions. The color difference ( ΔE* ) computing behaviors of the three formulas, other than CIELAB1976, changed depending on hue and chroma differences due to polar color difference considerations of their formulas, as expected.