An apparatus includes an obtaining part for obtaining image data of a document and a processing part for performing a color material saving process on the image data. The image data includes an edge part and a non-edge part. The apparatus includes a determining part configured to determine whether the document includes a low line-screen ruling area. When the document is determined not to include the low line-screen ruling area, the processing part is configured to perform a first process so that an amount of color material reduced for forming the non-edge part is greater than an amount of color material reduced for forming the edge part. When the document is determined to include the low line-screen ruling area, the processing part is configured to perform a second process so that the amounts of color material reduced for forming the edge part and the non-edge parts are uniform.