1. A color conversion definition creating method of creating a combined color conversion definition defining a coordinate conversion between coordinates on color spaces in accordance with a first color conversion definition defining a coordinate conversion between coordinates on a first color space having coordinate axes associated with four colors of cyan, magenta, yellow and black, respectively, and coordinates on a predetermined second color space, and a second color conversion definition defining a coordinate conversion between coordinates on a third color space having coordinate axes associated with four colors of cyan, magenta, yellow and black, respectively, and the coordinates on the second color space, said combined color conversion definition defining a coordinate conversion between coordinates on the first color space and coordinates on the third color space, said color conversion definition creating method comprising: a first black component derivation step of deriving a coordinate component of the black on the third color space associated with a predetermined representative coordinate in the first color space, on the representative coordinate, in accordance with the first color conversion definition and the second color conversion definition; a second black component derivation step of deriving a coordinate component of the black on the third color space associated with other coordinates excepting the representative coordinate in the first color space, in accordance with the coordinate component of the black on the third color space associated with the representative coordinate; and an out of black component derivation step of deriving coordinate components of cyan, magenta and yellow on the third color space, on the coordinates wherein the coordinate component of the black on the third color space is derived in said first black component derivation step and said second black component derivation step, in accordance with the coordinate component of the black derived, the first color conversion definition and the second color conversion definition.