1. A method for adjusting color balance of printhead means in a color printer, said method comprising the steps of: a) providing a matrix of image data, including a reference image data set for a reference image and a plurality of color-modified image data sets for plural color-modified images, said reference image data set comprising in-balance component color data values and each of said color-modified image data sets comprising out-of-balance component color values, each color-modified image data set having different out-of-balance component color data values; b) controlling said printhead means to print on a media sheet said reference image and each of said color-modified images at predetermined locations on a media sheet in accord with said matrix of image data, color representations of said reference image and each of said color-modified images being altered on said media sheet if said printhead means is not properly adjusted; and c) responding to a user selection of one image on said media sheet as said reference image and a position on said media sheet of said one image, by altering control signals to said printhead means in accord with component color values associated with said position of said one image in said matrix of image data.