For those colorants that both scatter andabsorb, the scattering and absorption tinting strengths must be specified. ASTM D 284 defines scattering tinting strength
as "the relative change in the scattering properties of a standard black material (with no scattering colorant present) when a specified amount of a white or chromatic scattering colorant is added to it" and absorption tinting strength as the relative change in the absorption properties of a standard white material when a specified amount of an absorbing colorant, black or chromatic, is added to it.