1. An image processing apparatus for converting an original image, comprising: an adjustment unit configured to apply processing of blurring an image and processing of adjusting a density for the original image to generate an adjusted image; a computing unit configured to generate a difference image that is a difference between the original image and the adjusted image obtained by said adjustment unit; and a compositing unit configured to composite the difference image and the original image based on a density of the difference image obtained by said computing unit and a density of the original image.