(57) Disclosed is a novel method of controlling dot gain of the halftone dots on a proof prints, which comprises the steps of: printing an object to be proofed including a control patch at different velocities, to obtain proof prints; obtaining dot gain values in respective prints; inputting the dot gain values to a memory of a proof press to be used for proof printing; calculating on the basis of the dot gain values and the printing velocities at which the printing is carried out; obtaining an approximate expression representing the relationship between the printing velocity and the dot gain value; inputting a desired dot gain value; obtaining an actual printing velocity corresponding to the desired dot gain value on the basis of the approximate expression; and carrying out an actual proof printing of the object at the actual printing velocity.