Method of creating lookup table, printing apparatus, lookup table, and printing method

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, the printing apparatus comprising a processor and a non-transitory computer readable medium storing the lookup table and code executable by the processor to implement the method, the method comprising:

• in a first process, determining the output value of the special gloss ink to be 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
• in a second process, determining the output value of the color ink at each lattice point by increasing an ink duty limit value which is an 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.