Color Matching

Color computer monitors, whether Cathode Ray Tubes (CRTs), Liquid Crystal Displays (LCDs) or plasma displays, create color by mixing the three light primaries: red, green, and blue. There are times when we wish to make sure that the colors on one monitor are the same as on another monitor. For instance, if we have carefully chosen the colors for an Air Traffic Control display, it would be prudent to make sure that the colors match across all displays of the same type and function.

Fortunately, color matching has been addressed for many years. In 1931, the Commission Internationale de l’Eclairage (CIE) developed a light measurement standard. The CIE conducted extensive color matching experiments with colored lights to develop a system based on human color perception (red, green, blue). The result was an international standard for color matching functions. With these color matching functions, any color can be precisely defined and matched.

The 1931 standard is known as CIE XYZ. Colors in the XYZ color space are specified by projection onto a two-dimensional plane. The coordinates of this plane are termed chromaticity co-ordinates. To assist the envisioning of this space, the chromaticity diagram was created for the CIE XYZ color space. All colors that can be humanly perceived can be plotted within this space. The area within the triangle represents the colors that can be displayed by a typical television monitor. The "+" indicates the "white point" of the monitor. (FAA Tech Rpt DOT/FAA/PM085019)

1931 CIE XYZ Chromaticity Diagram