1. A print color predicting method for predicting colors of a print produced by a printing press, comprising the steps of: generating a standard color chart comprising a plurality of color patches generated by the printing press, to which standard density conditions are set such that densities of color patches generated by two or more inks having a halftone dot percentage of a secured halftone dot percentage are the same as standard densities defined by a user, and to which respective halftone dot percentages of image data for the inks at predetermined intervals in the range from 0% to 100% halftone dot percentages are set; measuring said standard color chart to determine standard measured values; generating variation color charts, in which the density of each of the inks used to generate said print is independently varied by a given amount with respect to the standard density under the standard density conditions, and the densities of inks other than the varied ink are secured to said standard density conditions; measuring said variation color charts to determine varied measured values; when said inks are set to desired density variations for changing said standard densities for the inks to target densities desired by the user, adjusting said standard measured values using differences between said standard measured values and said varied measured values with respect to said inks set to said desired density variations; and predicting the colors of said print set to said density variations based on the relationship between the image data for generating said standard color chart and colorimetric values calculated based on the adjusted standard measured values.