Color image formation method and color image formation apparatus

DETAILED DESCRIPTION It is therefore an object of the invention to provide a color image formation method and a color image formation apparatus for executing appropriate color gamut compression depending on the amounts and distribution of reproduced color materials in addition to reproduced colors and input colors and reproducing a good color image.
According to the invention, in a color image recording apparatus for controlling reproduced colors in response to color material amounts of three or more colors, input color signals are converted into first color material amounts so as to minimize a distance as a first distance function defined on a predetermined color space, a second distance function defined on the predetermined color space is generated from the first color material amounts and the input color signals, and output color material amounts are determined from the input color signals so as to minimize a distance on the predetermined color space as the generated second distance function.
A color image is formed in response to the determined output color material amounts.
For example, the colors reproduced in response to the first color material amounts are found on the predetermined color space and the second distance function can be generated from the color coordinates of the reproduced colors, the first color material amounts, and the input color signals.
Further, color saturation is calculated from the first color material amounts and can also be added for generating the second distance function.
Alternatively, if the input color signals are outside the color reproduction range based on the input color signals, the first color material amounts, and the distance as the first distance function between the input color signals and the first color material amounts, which of overlight, equal lightness and oversaturation, and overdark the input color signals are with respect to the color reproduction range is determined, distribution or color saturation of the first color material amounts is recognized in response to the determination result, and the second distance function can also be generated from the distribution or color saturation of the first color materials, the input color signals, and the color coordinates of the reproduced colors