purity, <of a colour stimulus>
measure of the proportions of the amounts of the monochromatic stimulus and of the specified achromatic stimulus that, when additively mixed, match the colour stimulus considered
Note 1 to entry: In the case of purple stimuli, the monochromatic stimulus is replaced by a stimulus whose chromaticity is represented by a point on the purple boundary.
Note 2 to entry: The proportions can be measured in various ways (see "colorimetric purity" and "excitation purity").
Note 3 to entry: This entry was numbered 845-03-46 in IEC 60050-845:1987.
Note 4 to entry: This entry was numbered 17-1002 in CIE S 017:2011.