This invention provides a method of generating a dither matrix that stores each of a plurality of threshold values in each of elements for determining a status of dot formation of each print pixel of a print image to be produced on a printing medium by carrying out halftone processing on image data. The method includes: an evaluation value determining step of determining a second evaluation value for a second dot status based on a first evaluation value and an evaluation value change level, the first evaluation value being for a first dot status prior to determination of a storage element of a targeted threshold value among the plurality of threshold values, the second dot status hypothetically presuming that the storage element of the targeted threshold value has been determined, the evaluation value change level representing a level of variation of the evaluation value associated with change from the first dot status to the second dot status; a storage element determining step of determining an element for storing the targeted threshold value based on the determined second evaluation value; and a repeating step of repeating the evaluation value determining step and the storage element determining step, for at least some of the plurality of threshold values.