61‐2: Color Gamut of Multi‐Chromatic Displays

Abstract

It is said that multi-chromatic displays can achieve wider color gamut by using saturated color channels, while there are also claims that these displays lose brightness and/or color saturation for higher luminance colorful images. This topic has created some controversy in the display industry and at standards-setting organizations. This research examines color gamut volumes for a variety of simulated "multi-chromatic" or "multi-primary" (incorrect term) displays with combinations of cyan, magenta, and yellow color channels and/or white color channels. A twodimensional representation of color gamuts (i.e., gamut rings) illustrates that adding non-primary color channels to a trichromatic (red, green, and blue color channel) display reduces the overall chroma of color images at brighter levels.

Assessing color capability with gamut ring intersection

“…Unfortunately, a 3D rendering is difficult to represent on any 2D display medium, typically reduced to a series of 2D views of the 3D plot. The gamut ring diagram 7 is derived from the CIELAB gamut volume envelope of a test device rendered down into a standardized 2D form and has proved highly effective for assessing the color capability of a device 2,3,8,9 . However, the range of colors a display is capable of reproducing is often not what is important.…”

Analysis of color volume of multi‐chromatic displays using gamut rings

“…The existing input signals of nearly all displays are based on the mixing of RGB additive primary colors, and their system colorimetries are internationally standardized. Therefore, we should use the term “multi‐chromatic” rather than “multi‐primary” to refer to color displays that include extra optical color channels (beyond RGB), such as W and/or cyan, magenta, and yellow (CMY). The chromaticity coordinates of the optical color channels of RGB displays are not necessarily identical to those of the standard RGB assumed by the input signal.…”