An electrophotographic color image forming machine registers which a second color toner image on a first color toner image which has been previously formed on an image carrier to form a color image. The registered images are then transferred onto a recording sheet. The machine includes control apparatus that includes first and second exposure control modulators which respectively control an exposure amount of at least one of the first color toner images and the second color toner image. A smoothing processor controls at least one of a size and a position of at least one of the first and second color toner dot images within each of a plurality of pixels and a discriminator determines whether one of the size and the position of the dot image should be controlled. A hue corrector is provided which adjusts a ratio of the exposure amounts provided by the first and second exposure control modulators to control the first and second exposure control modulators on the basis of a discriminator result of the discriminator.