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The CIE system of colorimetry
The Commission Internationale de L’Éclairage (CIE) has defined a system that maps a spectral power distribution (SPD) of physics into a triple of numerical values – CIE XYZ tristimulus values – that form the mathematical coordinates of colour space. In this chapter, I describe the CIE system. In the following chapter, Colour science for video, I will explain how these XYZ tristimulus values are related to linear-light RGB values.
Colour coordinates are analogous to coordinates on a map (see Figure 25.1). Cartographers have different map projections for different functions: Some projections preserve areas, others show latitudes and longitudes as straight lines. No single map projection fills all the needs of all ...
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