CIE 1964 uniform colour space

three-dimensional, approximately uniform colour space produced by plotting in rectangular coordinates U*, V*, W*, quantities defined by the equations:
W* = 25 Y^1/3 – 17
U* = 13 W* (u − u_n)
V* = 13 W* (v − v_n)

Note 1 to entry:
Y, u, v describe the colour stimulus considered, and u_n, v_n describe a specified white achromatic stimulus, where u = u′, ; , .
See also "CIE 1976 uniform-chromaticity-scale diagram"

Note 2 to entry: The difference between two stimuli, ΔE*, is defined as the Euclidean distance between the points representing them in U*V*W* space and calculated as:
ΔE* = [(ΔU*)² + (ΔV*)² + (ΔW*)²]^1/2.

Note 3 to entry: The CIE 1964 uniform colour space is obsolete (except that it is still used in the calculation of colour rendering index). The currently recommended object colour spaces are the CIE 1976 L*a*b* colour space and the CIE 1976 L*u*v* colour space.

Note 4 to entry: This entry was numbered 17-153 in CIE S 017:2011.