This specification discloses a method and means for color detection and modification wherein the recognition of color is based on the definition of a three-dimensional color sub-space within a three-dimensional color universe. Chromaticity values are digitized and modeled as a function of brightness or luminance. Three eight-bit words (each having 256 values) are stored for each pixel of a digitized color picture. The first value is an approximation of luminance, while the second and third values represent variations of chromaticity or chrominance. Over sixteen million combinations of color values are available for each of over one million pixels in a 1024.times.1024 pixel array image. Pattern recognition techniques are used to determine if a given color value lies within the three-dimensional color sub-space. Additional means and method are disclosed to modify or manipulate the color defined by the color sub-space. A high-speed digital processing technique enables the real time modification of any portion of the color image within the display. By means of a unique weighting function, the operator is able to modify or insert colors and to provide a "smooth" edge or a "hard" edge as desired. The invention is particularly suited to the recognition or detection of color values on a textured, shaded and highlighted surface.