An approach is provided for processing pattern data which corresponds to a type of visual effect that is obtained by applying a transparent material to a recording medium to which colored material is applied according to image data. Arrangement information indicating, for example, an area of the image data relative to the recording medium is employed when calculating a magnification to be applied to a size of the pattern data. Further, the image data is converted in accordance with the calculated magnification, and an image is formed on the recording medium by using the converted image data and the magnified (reduced or enlarged) pattern data.