Line of purples

The straight boundary on a chromaticity diagram joining the red and violet ends of the visible spectrum. Its points represent purples that cannot be produced by a single wavelength of light.

Chromaticity diagram: A two-dimensional plot that represents chromaticity independently of a color’s overall brightness. The line is a boundary within this map of color chromaticities.
CIE 1931 color space: A color space defined by the CIE in 1931 using tristimulus values and a chromaticity diagram. Its chromaticity diagram provides the familiar framework for locating the line.
Colorimetry: The measurement and quantitative specification of color. Colorimetry uses chromaticity diagrams to describe colors without specifying brightness.
Spectral locus: The curved boundary on a chromaticity diagram traced by monochromatic lights across the visible spectrum. It forms the other boundary of the region whose straight closure is the line.
Visible spectrum: The range of electromagnetic wavelengths detectable by the human visual system. The line’s two endpoints correspond to the spectrum’s red and violet limits.
CIE 1931 xy chromaticity diagram: A two-dimensional diagram plotting the x and y chromaticity coordinates of colors in the CIE 1931 system. The line forms its straight boundary between the spectrum’s red and violet endpoints.
Color reproduction: The process of representing colors from an original scene on a display or in a printed image. The line identifies hues that color reproduction systems may fail to reach.
Color wheel: A circular arrangement of hues that represents relationships among colors. Its red-to-violet closure resembles the line but is not a chromaticity-diagram boundary.
Spectral color: A color sensation associated with light of a single wavelength in the visible spectrum. Unlike spectral colors, points along this line require mixtures of wavelengths.
Tristimulus values: Three numerical values representing a color stimulus through a specified set of color-matching functions. Chromaticity coordinates are derived by normalizing tristimulus values.

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Golan HeightsRelated: It marks the line from which Israeli forces captured the Golan Heights.