An image forming processor includes a generating unit and a correcting unit. The first characteristic quantity data obtaining unit obtains a set of first characteristic quantity data. The receiving unit receives data of an original image. The second characteristic data obtaining unit obtains a set of second characteristic quantity data based on the data of the original image. The generating unit generates at least one set of image data concerning the first characteristic quantity data. The display unit displays the at least one set of image data to prompt a user to specify one set of image data among the at least one set of image data. The correcting unit corrects the original image by using the set of second characteristic quantity data and a set of first characteristic quantity data that has been used to generate the one set of image data specified by the user.