Why are color gamut specifications sometimes calculated in CIE 1931 xy and sometimes in CIE 1976 uv colorspace?
The CIE 1931 xy colorspace is the more popular and widely recognized colorspace, and engineers are used to using this for calculations and charts. However it does not give equal area representation to different colors – in particular the size of the green area is overemphasized, but the blue area is underemphasized. This means that differences in green colors appear larger on the chart, than an equal difference in blue. The CIE 1976 u’v’ colorspace attempts to correct for this representation problem by scaling the chart so that colors are more equally represented. So CIE 1976 u’v’ is technically more useful for comparison purposes, but not as popular due to legacy usage and recognition.
