CIE Color Systems
CIE Color Systems The CIE, or Commission Internationale de l’Eclairage
(translated as the International Commission on Illumination), is the body
responsible for international recommendations for photometry and colorimetry.
In 1931 the CIE standardized color order systems by specifying the light
source (or illuminants), the observer and the methodology used to derive values
for describing color.
The CIE system
characterizes colour by a luminance Y and two colour coordinates x and y which
specify the point on the chromatic diagram. This system offers more precision
in colour measurement than do the Munsell system because the parameters are
based on the spectral power distribution of the light emitted from a coloured
object and is factored by sensitivity curves which have been measured for the
human eye.
Based
on the fact that the human eye has three different types of color sensitive cones, the response of
the eye is best described in terms of three "tristimulus values".
However, once this is accomplished, it is found that any color can be expressed
in terms of the two color coordinates x and y.
The
colors which can be matched by combining a given set of three primary colors (such as the blue, green, and red) are
represented on the chromaticity diagram by a triangle joining the coordinates
for the three colors.
The diagram given below represents
the mapping of human color perception in terms of two CIE parameters x and y. The spectral colors are distributed around the edge of the
"color space" as shown, and that outline includes all of the
perceived hues and provides a
framework for investigating color.
The CIE Color Systems utilize three coordinates to locate a color in a
color space. These color spaces include:
• CIE XYZ
• CIE L*a*b*
• CIE L*C*h°
