To make reproduction of gradations possible for images while utilizing usable ink in various kinds by a method wherein dot density modulation that modifies dot recording density to be defined as the rate of pixels discharged in a fixed quantity of ink to the whole pixels in accordance with image signals is executed.

Discharge quantity modulation is executed for the third kind gradation reproducing submode for reproducing the gradation for images in the same color with a fixed quantity of ink ejected for dot density recording at 100% and ink in the same color of one kind out of ink in the same color in a plurality of kinds. On the other hand, ink in the same color of another kind is selected out of the fourth kind gradation reproducing submode for reproducing the gradation for images in the same color with a fixed quantity of ink ejected for dot density recording at 100%. By using gradation reproducing submode in a plurality of kinds including at least one of the third kind and the fourth kind gradation reproducing submodes, gradations for images in the same color are reproduced.