To provide a color proof forming method that makes it possible to correct differences in color tone with respect to a printed matter in a color proof, and a program.

When the color proof is formed by exposing a recording medium according to dot image data, an area of the same color A in the dot image data is detected and a portion of a different color B in the area of the same color A is detected; and a color C in which the part of the color B is to be colored is determined according to the colors A and B and the recording medium is exposed so as to color the portion of the color B in the color C.