CIE Chromaticity Diagram in Computer Graphics

The chromaticity diagram represents the spectral colours and their mixtures based on the values of the primary colours(i.e  Red, Green, Blue) contained by them.  Chromaticity contains two parameters i.e, hue and saturation. When we put hue and saturation together then it is known as Chrominance.           

Chromaticity diagram represents visible colours using X and Y as horizontal and vertical axis. The various saturated pure spectral colours are represented along the perimeter of the curve representing the three primary colours – red, green and blue. Point C marked in chromaticity diagram represents a particular white light formed by combining colours having wavelength :

RED: 700 nm
GREEN : 546.1 nm
BLUE: 438.8 nm

In Chromaticity diagram colours on boundary are completely saturated. The corners in this chromaticity diagram represents by three primary colours (Red, Green and Blue).

C.I.E. Color Space:

It uses combination of 3 color values that are close to red, green and blue values which are plotted on a 3D space. Mapped physical wavelengths to perceived colors. It is used to identify the relative similarity and differences between colors. It is used to represents the wide range of colors.

Here,
X: Perceived color
Y: Perceived luminance
Z:Perceived color

Colors perceivable by the human eye:

Uses of C.I.E Chromaticity Diagram in Computer Graphics:

• It is used to evaluate a color against a gamut(range). 
• It is used to represent all chromaticities visible to the average person.
• It is used to find the range of colors. 
• It is used to find dominant and complementary colors.

Advantages:

•      Simple geometric construction for mixing two or more colours.
•      Both Perceptual attributes used: hue and saturation.