Kubelka-Munk equations:

When light is fall on some sample, some part of the light reflected, some are absorbed and some are scattered. If the sample is having opacity more than 70% then as per Kubelka Munk (established in 1931) following is the relation between reflectance, scattering and absorption of light:

K/S= (1 – 0.01R)²/2(0.01R)

The mathematical basis for all color matching software is the Kubelka-Munk series of equations. These equations state that for opaque samples such as textile materials, the ratio of total light absorbed and scattered by a mixture of dyes is equal to the sum of the ratios of light absorbed and scattered by the dyes measured separately. Where absorption is defined as "K" and scattering is defined as "S", Kubelka-Munk states that _:

(K/S) mixture = (K/S) dye 1 + (K/S) dye 2 + (K/S) dye 3 + ...

K/S is not a readily measurable quantity, but it can be calculated from the reflectance of a sample -- "R" -- by the Kubelka-Munk equation that states

 K/S= (1-R)²/2R

K/S  value is proportional to dye  concentration in the substrate

K/S=kC

Where k is constant and C is concentration of dyes or colorant