A method of creating a lookup table which describes a correspondence relationship between an input value to a printing apparatus for performing printing by ejecting ink onto a printing medium, and output values of a special gloss ink and a color ink of the printing apparatus, includes: a first process of determining the output value of the special gloss ink to be relatively low at a lattice point where an index value relating to color intensity is dark to be equal to or lower than a predetermined value, with regard to each lattice point of the lookup table; and a second process of determining the output value of the color ink at each lattice point by increasing an ink duty limit value which is the upper limit of the sum of the color ink that can be ejected onto a unit area of the printing medium, according to the determined output value of the special gloss ink.