C.I.E.
Diagram Information
The C.I.E. Chromaticity Diagram is a plot of X
versus Y for all visible colors. The Commission Internationale de l’Elcairage
(C.I.E.) XYZ model defines three primaries mingled in an additive manner called X, Y and Z
that can be combined to match any color humans see. This relates to the tristimulus theory
of color perception, which states that the human retina has 3 kinds of cones with peak
sensitivities to 580 nm (“red”), 545 nm (“green”) and 440 nm
(“blue”).
The Y primary was defined to match the luminous
efficiency function of the human eye. X and Z were obtained based on experiments involving
human observers. The chromaticity values are defined as:
x = X / (X+Y+Z)
y = Y / (X+Y+Z)
z = Z / (X+Y+Z)
Knowing x and y, z can be found as z = 1 - x - y.
Each point on the edge of the C.I.E. Chromaticity
Diagram denotes a pure color of a specific wavelength.
White is at the center where all colors combine
equally (x = y = z = 1/3).
|
