In a color ink jet recording system for performing color image recording on a recording medium using a plurality of recording heads and different color inks, the thinning ratio for at least one (e.g., black K) of the recording heads is set to be different from the thinning ratio for the remaining recording heads (e.g., cyan C, and the like). The total implantation quantity of the black ink can be twice the normal quantity without increasing the number of times of scan operations, and without causing boundary blur, and the print density of black can be increased.