1. A printing control apparatus for generating print data to be supplied to a printing unit to perform printing during main scans, the printing control apparatus comprising: a dot data generator configured to generate dot data from image data indicative of a image to be printed, the dot data representing a state of dot formation at each pixel; a contour line extractor configured to extract a first type contour line of a specific type image area represented by the dot data, the first contour line being parallel to a main scan direction, the specific type image area being composed of pixels at which specific type dots are to be formed; and a dot data adjuster configured to adjust the dot data so as to regularly reduce an amount of ink for forming dots on the first contour line.