A data processing apparatus includes a mask processor for performing a mask process for binary data, which is obtained by a binarization process using a dot arrangement pattern, by using mask patterns having print permitting pixels to generate binary data used for each of a plurality of scans of a print head to a same area of a print medium. An arrangement pattern of pixels that correspond to both of first data representing the print permitting pixels in at least one of the mask patterns and second data representing pixels to which dots are printed in the dot arrangement pattern satisfies the characteristics of (a) power spectrums of a low frequency region are smaller than power spectrums of a high frequency region, and (b) a peak of the power spectrums does not exist in a region lower side of half of the low frequency region.