Color processing apparatus, color processing method, color gamut setting apparatus, color gamut setting method, recording medium storing color processing program and recording medium storing color gamut setting program

A color gamut setting apparatus comprising:

• a color gamut setting unit comprising software and hardware that sets a color gamut in an output color space to which output color signals belong to, wherein:
• each output color signal comprises primary colorants and extra colorants,
• each output color signal corresponds to an input color signal belonging to an input color space, and
• the extra colorants of each output color signal is uniquely associated with the corresponding input color signal in the set color gamut;
• wherein
• the color gamut setting unit comprises:
• a first setting unit comprising software and hardware that sets a basic color gamut in the output color space, the basic color gamut in which each input color signal corresponding to the output color signal comprising the primary colorants and the extra colorants is associated with the extra colorants of the corresponding output color signal so that a phase of the input color signal corresponding to a color signal comprising the primary colorants of the corresponding output color signal is preserved;
• and
• a second setting unit comprising software and hardware that sets an extended color gamut by at least one of (i) increasing the extra colorants of the output color signals from a surface of the basic color gamut and (ii) decreasing the primary colorants of the output color signals on the surface of the basic color gamut, and
• in the extended color gamut, each input color signal is uniquely associated with the extra colorants of the corresponding output color signal.

A non-transitory computer readable medium storing a program causing a computer to execute a process for converting a target M-dimensional color signal in an input color space into an N-dimensional output color signal in an output color space where M and N are natural numbers and N>M, the process comprising:

• setting a color gamut in an output color space to which output color signals belong to, wherein:
• each output color signal comprises primary colorants and extra colorants,
• each output color signal corresponds to an input color signal belonging to an input color space, and
• the extra colorants of each output color signal is uniquely associated with the corresponding input color signal in the set color gamut;
• wherein the setting of the color gamut comprises:
• setting a basic color gamut in the output color space, the basic color gamut in which each input color signal corresponding to the output color signal comprising the primary colorants and the extra colorants is associated with the extra colorants of the corresponding output color signal so that a phase of the input color signal corresponding to a color signal comprising the primary colorants of the corresponding output color signal is preserved;
• and
• setting an extended color gamut by at least one of (i) increasing the extra colorants of the output color signals on a surface of the basic color gamut and (ii) decreasing the primary colorants of the output color signals on the surface of the basic color gamut, and
• in the extended color gamut, each input color signal is uniquely associated with the extra colorants of the corresponding output color signal;
• uniquely calculating (N−M) colorants of the converted output color signal from the target color signal with using plural color-signal pairs, in each pair, corresponding one of the (N−M) colorants of an output color signal in the output color space are associated with an input color signal in the input color space;
• and calculating the M colorants of the converted output color signal from the target color signal and the (N−M) colorants of the converted output color signal calculated.

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

• setting the color gamut in an output color space to which output color signals belong to, wherein:
• each output color signal comprises three primary colorants and at least two extra colorants,
• each output color signal corresponds to an input color signal belonging to an input color space, and
• the extra colorants of each output color signal is uniquely associated with the corresponding input color signal in the set color gamut;
• wherein the setting of the color gamut comprises:
• setting a basic color gamut in the output color space, the basic color gamut in which each input color signal corresponding to the output color signal comprising the primary colorants and the extra colorants is associated with the extra colorants of the corresponding output color signal so that a phase of the input color signal corresponding to a color signal comprising the primary colorants of the corresponding output color signal is preserved;
• and
• setting an extended color gamut by at least one of (i) increasing the extra colorants of the output color signals on a surface of the basic color gamut and (ii) decreasing the primary colorants of the output color signals on the surface of the basic color gamut, and
• in the extended color gamut, each input color signal is uniquely associated with the extra colorants of the corresponding output color signal.