To provide an image forming apparatus which enables gradation adjustments in a proof formation stage by using a binary dot image used to form printed matter and nearly maintaining a dot shape at this time, and is small in load of arithmetic processing since the gradation adjustments can be made through relatively simple processing.

A proof is formed of a dot gradation image having a dot constituted as a set of pixels, pixels having lower density than pixels constituting a dot being arranged along the entire periphery of the border of the dot.