Apple Color 1.5 - Manual (Page 155)

Chromaticity refers to the exact values a display uses to represent each of the three primary
colors. Different displays use different primary values; this can be seen on a chromaticity
diagram that plots the three primaries as points against a two-dimensional graph
representing hue and saturation within the visible spectrum. Since all colors represented
by a particular display are a mix of the three primaries, if the three primary points vary
from display to display, the entire gamut of color will shift.
While the chromaticity diagram shown above is useful for comparing displays on paper,
to truly represent the hue (color), saturation (intensity of color), and lightness (luminance
from black to white) that defines a complete gamut, you need to use a 3D color space.
When extruded into 3D space, the gamut and chromaticity of different devices create
different shapes. For example, the standard RGB color space can be represented with a
simple cube (as seen in the ColorSync Utility application):
155 Chapter 6 Monitoring Your Project