Chromaticity coordinates

Chromaticity coordinates are fractions of the tristimulus values X, Y and Z in the CIE color space that define a color. Chromaticity coordinates x, y and z are defined as follows:

x = X/(X + Y + Z)

y = Y/(X + Y + Z)

z = Z/(X + Y + Z)

The sum of all chromaticity coordinates is normalized to 1:

x + y + z = 1