Patent ID: 8184348

Claim:
A color separation method which is a process for converting an image signal into signals for colorants to be used by a printing apparatus, colorant value signals that include a colorant value for a dark colorant and a colorant value for a light colorant, said method comprising: a step of calculating a total colorant amount for the dark colorant and the light colorant by employing a relationship between a total colorant amount limitation value and a colorant amount, used by the printing apparatus, that includes a colorant amount for a colorant other than the dark colorant and the light colorant, wherein, as the total colorant amount, a difference between a total colorant amount limit value and a total colorant amount before color separation is performed; a step of employing the colorant amount before the color separation is performed, and calculating an increment available value for the total colorant amount of the dark colorant and the light colorant obtained after the color separation; a step of adding the difference to the total colorant amount of the dark colorant and the light colorant, based on a ratio of the increment available value; a step of calculating a density represented by a total of the dark colorant and the light colorant amount; and a step of employing the total colorant amount and the density to calculate the colorant value signals for the dark colorant and the light colorant.