1. An image processing apparatus, comprising: a judgment unit that judges whether a color image includes security dots; a calculation unit that calculates a blending ratio to blend each color element of the color image when the judgment unit judges that security dots are included in the color image, wherein the blending ratio is calculated so that the security dots are reproduced in a manner that is substantially undetectable by the human eye when a monochrome image into which the color image is converted is output on a print medium; and a converting unit that converts the color image into a monochrome image at the blending ratio calculated by the calculation unit.