To provide a device or the like which can exactly reproduce a color tone of a target printed matter by a relatively simple structure and for forming a proof of a stable color tone resistant to effects of kinds of light sources and variation of proof formation conditions.

The device for forming the proof of printed matter as an aggregate of dots on the basis of digital image data of the printed matter which has images of a plurality of printing colors overlapped forms an image of at least one color of the printing colors with the use of two or more kinds of dots similar in the color tone to each other, and white dots or dots of a color difference of not larger than 10 from white.