Жарқын спектрдің түстері

Color evoked by a single wavelength of light in the visible spectrum

A spectral color is a color that is evoked by monochromatic light, i. e. either a spectral line with a single wavelength or frequency of light in the visible spectrum, or a relatively narrow spectral band (e. g. lasers). Every wave of visible light is perceived as a spectral color; when viewed as a continuous spectrum, these colors are seen as the familiar rainbow. Non spectral colors (or extra spectral colors) are evoked by a combination of spectral colors.

In color spaces which include all, or most spectral colors, they form a part of boundary of the set of all real colors. When considering a three dimensional color space (which includes luminance), the spectral colors form a surface. When excluding luminance and considering a two dimensional color space (chromaticity diagram), the spectral colors form a curve known as the spectral locus. For example, the spectral locus of the CIEXYZ chromaticity diagram contains all the spectral colors (to the eye of the standard observer). A trichromatic color space is defined by three primary colors, which can theoretically be spectral colors. In this case, all other colors are inherently non spectral. In reality, the spectral bandwidth of most primaries means that most color spaces are entirely non spectral. Due to different chromaticity properties of different spectral segments, and also due to practical limitations of light sources, the actual distance between RGB pure color wheel colors and spectral colors shows a complicated dependence on the hue. Due to the location of R and G primaries near the 'almost flat' spectral segment, RGB color space is reasonably good with approximating spectral orange, yellow, and bright (yellowish) green, but is especially poor in reproducing the visual appearance of spectral colors in the vicinity of central green, and between green and blue, as well as extreme spectral colors approaching IR or UV. Spectral colors are universally included in scientific color models such as CIE 1931, but industrial and consumer color spaces such as sRGB, CMYK, and Pantone, do not typically include any spectral colors. Exceptions include Rec. 2020, which uses three spectral colors as primaries (and therefore only includes precisely those three spectral colors), and color spaces such as the ProPhoto RGB color space which use imaginary colors as primaries. In color models capable of representing spectral colors,The HSL and HSV systems do not qualify, because many spectral colors lie rather far from their gamut. such as CIELUV, a spectral color has the maximal saturation. In Helmholtz coordinates, this is described as 100% purity.

In dichromatic color vision there is no distinction between spectral and non spectral colors. Their entire gamut can be represented by spectral colors. This is true for dichromats with photoreceptor cells with overlapping spectral sensitivity curves. If the spectral sensitivity curves do not overlap, then all colors except for the extremes (where one of the cones is not excited) would be non spectral. However, there are no known vision systems where the cones' spectral sensitivity curves do not overlap.