Abstract: In a method for forming a duplicate image by reading an original image from an original sheet and forming a duplicate image according to the original image, to allow the designation of a number of regions for forming duplicate regional images, from an overall image, with desired color separation or other various attributes to be carried out accurately, promptly and simply by mounting the original sheet only once on a digitizer or the like without regard to the number of processes of forming a duplicate image, a plurality of regions designated on a single original sheet are stored in a storage device such as computer memory, either the designated region stored in the storage device or the region other than the designated region is defined as an effective region, a duplicate image of only the effective region is formed for a first process of forming a duplicate image, only the region other than the effective region for the first process of forming a duplicate image is defined as a new effective region, and a du