Pure wavelengths are on the horseshoe-shaped outline of the CIE 1931 space. The straight line connecting the ends of the horseshoe is the line of purples, which

Pure wavelengths are on the horseshoe-shaped outline of the CIE 1931 space. The straight line connecting the ends of the horseshoe is the line of purples, which also isn't monochromatic. https://en.wikipedia.org/wiki/Chromaticity#/media/File:PlanckianLocus.png https://en.wikipedia.org/wiki/Chromaticity#/media/File:Planc...