triangle to enclose a much larger color gamut. An equivalent, simpler change is to allow negative numbers in color channels, so that the represented colors can extend out of the color triangle formed by the primaries. However these only extend the colors that can be represented in the image encoding; neither trick extends the gamut of colors that can actually be rendered on a display device. Supplementary colors can widen the color gamut of a display, since it is no longer limited to the interior of a triangle formed by three primaries at its corners, e.g. the CIE 1931 color space. Recent technologies such as Texas Instruments's BrilliantColor augment the typical red, green, and blue channels with up to three other primaries: cyan, magenta, and yellow. Note that cyan would be indicated by negative values in the red channel, magenta by negative values in the green channel, and yellow by negative values in the blue channel, validating the use of otherwise fictitious negative numbers in the color channels. Mitsubishi and Samsung (among others) use BrilliantColor in some of their TV sets to extend the range of displayable colors. The Sharp Aquos line of televisions has introduced Quattron technology, which augments the usual RGB pixel components with a yellow subpixel. However, formats and media that allow or make use of the extended color gamut are at present extremely rare. Because humans are overwhelmingly trichromats or dichromats one might suppose that adding a fourth "primary" color could provide no practical benefit. However humans can see a broader range of colors than a mixture of three colored lights can display. The deficit of colors is particularly noticeable in saturated shades of bluish green (shown as the left upper grey part of the horseshoe in the diagram) of RGB displays: Most humans can see more vivid blue-greens than any color video screen can display. See also Footnotes References Television technology