Abstract: A method and system for alternatingly applying different colors to a realistic computer generated graphic image while preserving the effects of shading, highlights, reflectors and other lighting effects. A user selects a "New Color" to apply to an image and picks an "Original Color" from the image in an area not subject to extreme lighting effects. The difference between the parameters of these two colors in (H,S,V) coordinates is determined and applied to every pixel in a segment of the image to calculate a replacement pixel color. Tools are provided to allow the user to divide an image into segments to which color modification can be individually applied.

Abstract: A system and method for correcting errors in the colors of an image in a computer-aided design system; such errors being introduced by a process such as the production of a hard-copy of an image displayed on a graphic CRT. Tools are provided for the user to select "registered" colors and to determine, either manually or by system calculation, corrected values of such registered colors that will produce the desired image on the hard-copy. The manual selection technique provides tools for iteratively creating charts of related, but varied, color squares and sending the charts to the output device. The resulting hard-copy is compared by the user with the chart displayed on the CRT and the user's selection is processed by the system. In the other technique, the hard-copy image of such color chart is re-entered to the system through an input device and the error between the original and processed color patches is calculated and applied to determine corrected colors.