Color Gamut

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220px-Colorspace copy gamut

In color theory, the gamut of a device or process is that portion of the color space that can be represented, or reproduced. Color gamut is a measure of how large the color range is according to a specific color model (RGB, CMYK, etc.). Generally, the color gamut is specified in the huesaturation plane, as a system can usually produce colors over a wide intensity range within its color gamut; for a subtractive color system (such as used in printing), the range of intensity available in the system is for the most part meaningless without considering system-specific properties (such as the illumination of the ink). In general, gamut is the range of something compared to its reference range. For example, the RGB color gamut is a smaller subset of the larger spectrum of all visible color and light.

When certain colors cannot be expressed within a particular color model, those colors are said to be out of gamut. For example, while pure red can be expressed in the RGB color space, it cannot be expressed in the CMYK color space; pure red is out of gamut in the CMYK color space.

Adding a certain mapping function between the color model and a certain reference color space results in a definite “footprint” within the reference color space. This “footprint” is known as a gamut, and, in combination with the color model, defines a new color space. For example, Adobe RGB and sRGB are two different absolute color spaces, both based on the RGB model.

color space is the type and number of colors which originate from the combinations of color components of a color model. We speak of a color space because a color model defines a—mostly three-dimensional —coordinate system by its components, and in its space one point corresponds to one specific color.

In the most generic sense of the definition above, color spaces can be defined without the use of a color model. These spaces, such as Pantone, are in effect a given set of names or numbers which are defined by the existence of a corresponding set of physical color swatches.