An image forming apparatus, an image forming method, a program, and a recording medium that succeed in reducing recording agent consumption without causing image quality degradation are provided. A modification region processing section detects, out of image data, A locations where a region identification signal provided from a region separation processing section changes from a ground region mode to a character region mode, and vice versa, as the boundary between the ground region and the character region, and thereby specifies a modification region which is continuous with the ground region and overlaps with a part of a periphery of the character region which is contiguous to the ground region. The modification region is assigned color data indicating a color that can be represented by the recording agent for use in ground region formation thereby to generate image data.