Color processing device that converts combination of colors into larger number of combination of colors, color processing method, and storage medium

A non-transitory computer readable medium storing a program causing a computer to execute a process for color processing, the process comprising:

• converting a combination of values of N−1 colors, which are obtained by eliminating a specific color included in N colors from an input-color signal expressing a color by a combination of values of the N colors, into a corresponding combination of values of M−1 colors, N being equal to or larger than 4, M being larger than N;
• and
• if a total value of the values of the M−1 colors after the conversion and a value of the specific color included in the input-color signal exceeds a predetermined limit value, changing a value of at least one of M colors, which are obtained by adding the specific color to the M−1 colors, such that the total value becomes the limit value or smaller, and outputting values of the M colors as an output color signal,
• wherein the M colors of the output color signal includes a basic color and a non-basic color, and
• wherein, when a total value of the values of the M colors exceeds the limit value, the process further comprises determining whether or not a total value of values of remaining colors exceeds the limit value, the remaining colors being obtained by eliminating the non-basic color from the M colors, changing a value of the non-basic color such that the total value of the values of the M colors becomes the limit value or smaller if the total value of the values of the remaining colors is the limit value or smaller, and changing the value of the non-basic color into a predetermined minimum value and changes a value of the basic color such that the total value of the values of the M colors becomes the limit value or smaller if the total value of the values of the remaining colors exceeds the limit value.

An image processing method comprising:

• converting a combination of values of N−1 colors, which are obtained by eliminating a specific color included in N colors from an input-color signal expressing a color by a combination of values of the N colors, into a corresponding combination of values of M−1 colors, N being equal to or larger than 4, M being larger than N;
• and
• if a total value of the values of the M−1 colors after the conversion and a value of the specific color included in the input-color signal exceeds a predetermined limit value, changing a value of at least one of M colors, which are obtained by adding the specific color to the M−1 colors, such that the total value becomes the limit value or smaller, and outputting values of the M colors as an output color signal,
• wherein the M colors of the output color signal includes a basic color and a non-basic color, and
• wherein, when a total value of the values of the M colors exceeds the limit value, the method further comprises determining whether or not a total value of values of remaining colors exceeds the limit value, the remaining colors being obtained by eliminating the non-basic color from the M colors, changing a value of the non-basic color such that the total value of the values of the M colors becomes the limit value or smaller if the total value of the values of the remaining colors is the limit value or smaller, and changing the value of the non-basic color into a predetermined minimum value and changes a value of the basic color such that the total value of the values of the M colors becomes the limit value or smaller if the total value of the values of the remaining colors exceeds the limit value.