Color image forming apparatus

Abstract

In order to realize a method of color correction which is capable of performing the UCR compensating for the non-linearity of the superposed densities and the non-linear color correction meeting the non-linearity of the superposed densities at high accuracy with a configuration in substantially the same scale as the conventional linear UCR and linear masking techniques, there is provided a color correction method comprising first conversion means for converting the C, M, Y density information by a monotonously incremental non-linear function with a similarly monotonously incremental derivative, matrix means, and second conversion means for converting the same density information by a monotonously incremental non-linear function with a monotonously decremental derivative. In another aspect, there is provided four-color reproduction means comprising first conversion means for converting the C, M, Y information by a monotonously incremental non-linear function with a similarly monotonously incremental derivative, second conversion means, for effecting the conversion with a monotonously incremental non-linear function with a monotonously decremental derivative, and black separation means, subtraction means and matrix means interposed between the first and second conversion means for controlling the densities of the four inks to implement color recording.