Applying brightness, whiteness, and color measurements to color removal

Brightness measurements alone are not enough to evaluate how efficiently color is removed from pulp. Whiteness measurements and color data are also needed but are more difficult to interpret. CIE L *a*b* is the most commonly used color system, but CMC color difference mathematics may be needed as well. Absorption coefficients give the bleaching chemist an objective may to measure the amount of colorant remaining after each stage of color removal.