Chromaticity

The quality of a color regardless of its luminance

Chromaticity is an objective specification of the quality of a color regardless of its luminance. Chromaticity consists of two independent parameters, often specified as hue and saturation, or as x and y coordinates in the CIE 1931 color space.

Definition

Chromaticity is defined by the International Commission on Illumination (CIE) as the quality of a color as determined by its dominant or complementary wavelength and purity taken together. It is a part of the color appearance model that describes how colors are perceived by the human eye.

Chromaticity Coordinates

In the CIE 1931 color space, chromaticity is represented by the chromaticity coordinates (x, y). These coordinates are derived from the tristimulus values X, Y, and Z, which are calculated from the spectral power distribution of a light source. The x and y coordinates are calculated as follows:

x = \frac{X}{X + Y + Z}

y = \frac{Y}{X + Y + Z}

These coordinates are plotted on the CIE chromaticity diagram, which is a two-dimensional representation of color space.

Applications

Chromaticity is used in various applications, including:

• Colorimetry: The science of measuring colors and assigning them numerical values.
• Display technology: Ensuring accurate color reproduction in devices such as monitors, televisions, and projectors.
• Lighting design: Selecting light sources with specific chromaticity characteristics for aesthetic or functional purposes.

Related Concepts

• Color temperature: A measure of the color of light emitted by a source, expressed in Kelvin.
• Gamut: The complete range or scope of colors that can be produced by a device or represented in a color space.
• Metamerism: The phenomenon where colors appear the same under certain lighting conditions but different under others.

See Also

• Color theory
• Color space
• Color science

References

• R. W. G.,

 The Reproduction of Colour, 
  
 Wiley-IS&T, 
 2004, 
  
  
 ISBN 978-0-470-02425-0,

International Commission on Illumination (CIE)(link). {{{website}}}.

Accessed 2023-10-01.

External Links

• CIE Official Website
• Colour Science

Chromaticity

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  Planckian Locus

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  sRGB Gamut within CIExyY Color Space Mesh

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  CIE 1976 UCS