RGB Electronic Test Targets

With the advent of digital cameras, there is a transition of graphics data now being stored in RGB form and not in the traditional CMYK format. A new set of RGB test targets is being presented that helps designers trouble shoot problem images. One of the new test targets is an update of the "Granger Rainbow". The new rainbow presents RGB combinations that are physiologically uniform in hue and saturation. The target displays color from neutral to full saturation for half of the display. The second half of the display is used to darken the fully saturated colors to the black point. This target is very useful in testing the ability of a transformation to map the convex hull of the real world of color.

A second larger number of targets is used to explore the ability of a gamut mapping scheme to reproduce colors and color gradients within the convex hull of the color space. These targets are used in the diagnoses of problems of reproducing computer generated images. The requirement of gamut mapping to reproduce an RGB image sometimes produces images with contours. The new targets will aid in identifying color regions where gamut mapping may produce problems.