1. An image processing apparatus, comprising: a print control unit configured to cause a printing apparatus to print, on a sheet, an image stored in a memory so that the image is printed on the sheet with a density lower than a predetermined density value; an acquiring unit configured to acquire a read image obtained by reading, by a reading apparatus, the sheet on which the image is printed by the print control unit and information is added by a user; a specifying unit configured to specify an area, in the read image acquired by the acquiring unit, that corresponds to a difference of a plurality of color components greater than a predetermined threshold, as an information area corresponding to the information added to the sheet by the user; and a combining unit configured to combine an image of the information area specified in the read image by the specifying unit and the image stored in the memory.