Line of purples

In color theory, the line of purples or the purple boundary is the locus on the edge of the chromaticity diagram between extreme spectral red and violet. Except for the endpoints, colors on the line of purples are not spectral. Line-of-purples colors and spectral colors are the only ones which are considered fully saturated in the sense that for any given point on the line of purples there exists no color involving a mixture of red and violet that is more saturated than it. There is no monochromatic light source able to generate a purple color. Instead, every color on the line of purples is produced by mixing a unique ratio of fully saturated red and fully saturated violet, at the extreme points of visibility on the spectrum of pure hues.