Printing method including gradation region ink amount calculation step

A printing method comprising:

• a color space conversion step of converting a color space of image data from a device-dependent color space to a uniform color space;
• a gradation determination step of determining, using a distribution of a pixel group and a color change included in a predetermined range from a pixel of interest in the converted uniform color space, whether the pixel group forms a gradation;
• and
• a gradation region ink amount calculation step of calculating an ink amount of the pixel group determined to form the gradation, wherein
• the gradation region ink amount calculation step includes
• an array information acquisition step of acquiring whether pixel values constituting the pixel group determined to form the gradation are arranged linearly, in a planar manner, or in a polyhedron manner in the uniform color space,
• a grating color value calculation step of determining a grating color value which is a color value of a grating point in the array,
• a grating ink amount calculation step of calculating, using the determined grating color value, a grating ink amount which is an ink amount of the grating point in the array, and
• an interpolation calculation step of calculating an ink amount of the pixel group determined to form the gradation by interpolation using the calculated grating ink amount.