To exactly adjust color conversion while suppressing density nonuniformity.

When printing out a chart for the control or confirmation of color conversion onto recording paper concerning a color conversion control method for color printer, a checkered pattern alternately arranging white and black squares having one side for 2 to 4 mm like a checker board is printed out at the section of recording paper to become the background of chart. Since white and black squares are mixed almost equally in an area ratio inside any arbitrary background area wider than fixed scale in this checkered pattern, a duty ratio gets almost uniform within a print picture and load applied to a head is reduced. Thus, density nonuniformity is suppressed and exact color conversion can be controlled.