Spectral color
Encyclopedia
A spectral color is a color
that is evoked by a single wavelength
of light
in the visible spectrum
, or by a relatively narrow band of wavelengths. Every wavelength of light is perceived as a spectral color, in a continuous spectrum; the colors of sufficiently close wavelengths are indistinguishable.
The spectrum is often divided up into named colors, though any division is somewhat arbitrary: the spectrum is continuous. Traditional colors include: red
, orange, yellow
, green
, blue
, and violet
.
The division used by Newton
, in his color wheel, was Red, Orange, Yellow, Green, Blue, Indigo and Violet; a mnemonic
for this order is Roy G. Biv
. In modern divisions of the spectrum, indigo is often omitted as simply a tone of blue or violet.
Color
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
that is evoked by a single wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
of light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
in the visible spectrum
Visible spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of...
, or by a relatively narrow band of wavelengths. Every wavelength of light is perceived as a spectral color, in a continuous spectrum; the colors of sufficiently close wavelengths are indistinguishable.
The spectrum is often divided up into named colors, though any division is somewhat arbitrary: the spectrum is continuous. Traditional colors include: red
Red
Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...
, orange, yellow
Yellow
Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–590 nm is yellow, as is light with a suitable mixture of red and green...
, green
Green
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
, blue
Blue
Blue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440–490 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...
, and violet
Violet (color)
As the name of a color, violet is synonymous with a bluish purple, when the word "purple" is used in the common English language sense of any color between blue and red, not including either blue or red...
.
The division used by Newton
Isaac Newton
Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...
, in his color wheel, was Red, Orange, Yellow, Green, Blue, Indigo and Violet; a mnemonic
Mnemonic
A mnemonic , or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something,...
for this order is Roy G. Biv
Roy G. Biv
ROYGBIV is an acronym for the visible part of the electromagnetic light spectrum:* Red* Orange* Yellow* Green* Blue* Indigo* VioletA rainbow spans a continuous spectrum of colors; the distinct bands are an artifact of human color vision...
. In modern divisions of the spectrum, indigo is often omitted as simply a tone of blue or violet.
Non-spectral colors
Among some of the colors that are not spectral colors are:- GrayscaleGrayscaleIn photography and computing, a grayscale or greyscale digital image is an image in which the value of each pixel is a single sample, that is, it carries only intensity information...
(achromatic) colors, such as whiteWhiteWhite is a color, the perception of which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in nearly equal amounts and with high brightness compared to the surroundings. A white visual stimulation will be void of hue and grayness.White light can be...
, gray, and blackBlackBlack is the color of objects that do not emit or reflect light in any part of the visible spectrum; they absorb all such frequencies of light... - Any color obtained by mixing a gray-scale color and yet another color (either spectral one or not spectral), such as pinkPinkPink is a mixture of red and white. Commonly used for Valentine's Day and Easter, pink is sometimes referred to as "the color of love." The use of the word for the color known today as pink was first recorded in the late 17th century....
, which is a mixture of a redRedRed is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked eye...
dish color and white. - PurplePurplePurple is a range of hues of color occurring between red and blue, and is classified as a secondary color as the colors are required to create the shade....
colors, which in color theoryColor theoryIn the visual arts, color theory is a body of practical guidance to color mixing and the visual impacts of specific color combinations. Although color theory principles first appeared in the writings of Leone Battista Alberti and the notebooks of Leonardo da Vinci , a tradition of "colory theory"...
also include magentaMagentaMagenta is a color evoked by light stronger in blue and red wavelengths than in yellowish-green wavelengths . In light experiments, magenta can be produced by removing the lime-green wavelengths from white light...
colors, roseRose (color)Rose is the color halfway between red and magenta on the HSV color wheel, also known as the RGB color wheel, on which it is at hue angle of 330 degrees.Rose is one of the tertiary colors on the HSV color wheel...
colors, and other colors on the line of purplesLine of purplesIn color theory, the line of purples or the purple boundary is the locus of non-spectral colors on the edge of the chromaticity diagram between red and violet. Like spectral colors, purples can be considered fully saturated in the sense that for any given point on the line of purples there exists...
, which are various mixtures of violet and red light.