1. An image processor comprising: a storing unit that stores at least one of one or more process colors and one or more spot colors that are different from the one or more process colors according to a predetermined key word; a searching unit that extracts the one or more process colors and the one or more spot colors stored in the storing unit according to an entered key word; a substitution unit that, when color substitution and a substituted color are set for a process color of an image data or a drawing instruction entered from a terminal, substitutes color information of the process color with color information of the substituted color and creates new color information according to the image data or the drawing instruction; and an image processing unit that performs image processing depending on the image data or the drawing instruction, according to the new color information substituted by the substitution unit, wherein color information for each spot color is stored in the storing unit, and the substitution unit creates the new color information based on the color information stored in the storing unit.