Indigo
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Reverted edits by [[Special:Contributions/Pink!Teen|Pink!Teen]] ([[User talk:Pink!Teen|talk]]) to last version by 128.174.228.52
{{This|the color|Indigo (disambiguation)}}
{{infobox color
|title=Indigo
|textcolor=White
|pic=Image:Indian indigo dye lump.jpg
|wavelength=420–450
|hex= 4B0082
|r= 75|g=0|b=130 |sRGB=1
|c=Not|m=possible|y=in|k=CMYK
|h=275|s=100|v=51
|source=[[Web colors#X11 color names|HTML/CSS]]<ref name="css3-color">[http://www.w3.org/TR/css3-color/#svg-color W3C TR CSS3 Color Module, SVG color keywords]. W3C. (May 2003). Retrieved on [[2007-12-14]].</ref>
}}
'''Indigo''' is the [[color]] on the [[electromagnetic spectrum]] between about 420 and 450 [[nanometre|nm]] in [[wavelength]], placing it between [[blue]] and [[violet (color)|violet]]. Color scientists do not usually recognize indigo as a significant color category, and generally classify wavelengths shorter than about 450 nm as violet.<ref name=hunt>{{cite book | title = Measuring Color | author = J. W. G. Hunt | year = 1980 | publisher = Ellis Horwood Ltd | isbn = 0-7458-0125-0}}</ref>
Indigo and violet are different from [[purple]], which cannot be seen on the electromagnetic spectrum but can be achieved by mixing mostly [[blue]] and part [[red]] light.
One can see spectral indigo by looking at the reflection of a fluorescent tube on a non-recorded [[compact disc]]. This works because the CD functions as a [[diffraction grating]], and a [[fluorescent lamp]] generally has a peak at 435.833 nm (from [[mercury (element)|mercury]]), as is visible on the [[Fluorescent lamp#Phosphors and the spectrum of emitted light|fluorescent lamp spectrum]].
{{wikisourcepar|Littell's Living Age/Volume 145/Issue 1869/Definition of the Color Indigo|An 1869 debate over whether indigo is really the color indicated on the spectrum.}}
==Distinction between four shades of indigo==
Like many other colors ([[Orange (colour)|orange]] and [[violet (color)|violet]] are the best-known), indigo gets its name from an object in the natural world—the plant named ''[[indigo plant|indigo]]'' once used for dyeing cloth (see also [[Indigo dye]]).
The color ''electric indigo'' is an approximation of ''spectrum indigo''. This is the brightest color indigo that can be approximated on a computer screen—it is the color between the [[web color]] [[blue]] and the color electric [[violet (color)|violet]].
The web color ''blue violet'' or ''deep indigo'' is a shade of indigo brighter than pigment indigo but not as bright as electric indigo.
The color ''pigment indigo'' is equivalent to the [[web color]] indigo and approximates the color indigo that is usually reproduced in pigments and colored pencils.
The color of ''indigo dye'' is a different color than either spectrum indigo or pigment indigo. This is the actual color of the dye from the indigo plant when swatched onto raw fabric. A vat full of this dye is a darker color, approximating the web color [[Midnight Blue]].
When specifying the color ''indigo'', it is necessary to indicate which particular one of these four major shades of indigo you are referring to.
===Electric indigo===
{{infobox color|
title=Electric Indigo|textcolor=white|
hex=6600FF|
r=102|g= 0|b=255|
c= 75|m= 78|y= 0|k= 0|
h=264|s=100|v=100
|source=[http://tx4.us/moacolor.htm HTML Color Chart @264]}}
In an RGB [[color space]], spectral indigo and violet must be approximated by purples, that is, by mixing a little red with a lot of blue. Spectral indigo is closely approximated by the color '''electric indigo'''. This sample was taken directly from the [[CIE chromaticity diagram]] opposite the 430 nanometer line. It is much brighter than the pigment indigo reproduced below. Spectrum Indigo fits nicely between spectrum [[violet (color)|violet]] and spectrum [[blue]] as can be seen in the color bands displayed below.
It is impossible to represent spectrum indigo exactly on a computer screen, because true spectrum indigo is outside the color triangle or [[gamut]] of the RGB [[color space]] defined by the monitor primaries.
=== Not viewed as a color in its own right ===
Indigo was defined as a spectral color by Sir [[Isaac Newton]] when he divided up the [[optical spectrum]], which has a continuum of [[wavelength]]s. He specifically named [[seven]] colors primarily to match the seven notes of a western [[major scale]], because he believed sound and light were physically similar, but also to link colors with the (known) [[planet]]s, [[day]]s of the [[week]], and other lists that had seven items.
The human eye is relatively insensitive to [[hue]] changes in the wavelengths between blue and violet, where Newton defined indigo to be; most individuals do not distinguish indigo from blue and violet. For this reason, some commentators, including [[Isaac Asimov]], hold that indigo should not be regarded as a color in its own right, but merely as a shade of blue or violet.
Color scientists typically divide the spectrum at about 450 nm between violet and blue, with no indigo.<ref name=hunt/><ref>{{cite book | url = http://books.google.com/books?vid=ISBN3527405038&id=1oDOWr_yueIC&pg=PA214&lpg=PA214&ots=Jrfi5sPBhk&dq=indigo+spectra+blue+violet+date:1990-2007&sig=Rm2xP5mIgyGJ1a1pbfAt65QSf0I#PPA214,M1 | title = Fundamentals of Atmospheric Radiation | author = Craig F. Bohren and Eugene E. Clothiaux |publisher = Wiley-VCH | year = 2006 | isbn = 3527405038}}</ref> Others continue to accept it,<ref> Tansley, David V. ''Subtle Body: Essence and Shadow'' New York: 1984 Avon (Art and Cosmos series--Jill Purce, Editor) It is pointed out that [[New Age]] [[artist]]s and [[philosopher]]s accept indigo as a spectrum color because it is used to represent one of the seven [[chakra]]s (the sixth) of the [[subtle body]].</ref> as it has been accepted traditionally as one of [[Isaac Newton|Newton]]'s named colors of the [[spectrum]] along with [[red]], [[orange (color)|orange]], [[yellow]], [[green]], [[blue]], and [[Violet (color)|violet]].
===Deep indigo (web color blue-violet)===
{{infobox color|
title=Blue-Violet|textcolor=white|
hex=8A2BE2|
r=138|g= 43|b=226|
c= 63|m= 81|y= 0|k= 0|
h=271|s= 81|v= 89|
|source=[[Web colors#X11 color list|X11]]}}
At right is displayed the [[web color]] '''blue-violet''', a color intermediate in brightness between electric indigo and pigment indigo. This color is also called '''deep indigo'''.
{{-}}
===Pigment indigo (web color indigo)===
{{infobox color|
title=Pigment Indigo|textcolor=white|
hex=4B0082|
r= 75|g= 0|b=130|
c= 42|m=100|y= 0|k= 49|
h=275|s=100|v=50
|source=[[Web colors#X11 color list|X11]]}}
The color box at right displays the [[web color]] Indigo which is equivalent to '''pigment indigo''', the color indigo as it would be reproduced by artists' paints as opposed to the brighter indigo above (electric indigo) that it is possible to reproduce on a computer screen.
Pigment indigo can be obtained by mixing 55% pigment [[cyan]] with about 45% pigment [[magenta]].
Compare the subtractive colors to the additive colors in the two primary color charts in the article on [[primary colors]] to see the distinction between electric colors as reproducible from light on a computer screen (additive colors) and the pigment colors reproducible with pigments (subtractive colors); the additive colors are a lot brighter because they are produced from light instead of pigment.
Pigment indigo (web color indigo) represents the way the color indigo was always reproduced in pigments, paints, or colored [[pencil]]s in the [[1950]]s.
By the [[1970]]s, because of the advent of [[psychedelic]] [[art]], artists became used to brighter pigments, and pigments called "bright indigo" or "bright blue-violet" that are the pigment equivalent of the electric indigo reproduced in the section above became available in artists' pigments and colored pencils.
{{-}}
===Indigo dye===
{{infobox color|
title=Indigo Dye|textcolor=white|
hex=00416A|
r= 0|g= 65|b=106|
c= |m= |y= |k= |
h=203|s=100|v= 42
|source=[http://tx4.us/nbs/nbs-i.htm ISCC-NBS]}}
At right is displayed the color '''indigo dye''', an approximation of the color of a swatch of [[indigo dye]].
Sample of Indigo Dye color: [http://tx4.us/nbs/nbs-i.htm ISCC-NBS Dictionary of Color Names (1955)--Color Sample of Indigo Dye (Indigo color sample #179)]
{{-}}
==Indigo in human culture==
'''[[New Age]] [[Philosophy]]'''
* The color electric indigo is used to symbolically represent the sixth [[chakra]] (called [[Ajna]]), which is said to include the [[third eye]]. This ''chakra'' is believed to be related to [[intuition]] and [[gnosis]] (spiritual knowledge). <ref> Graham, Lanier F. (editor) ''The Rainbow Book'' Berkeley, California:1976 Shambala Publishing and The Fine Arts Museums of San Francisco (Handbook for the Summer 1976 exhibition ''The Rainbow Art Show'' which took place primarily at the [[De Young Museum]] but also at other museums) ''Indigo'' Pages 152-153 The color indigo is stated to represent intuition. </ref>
'''[[Parapsychology]]'''
* [[Psychic]]s who claim to be able to observe the [[aura (paranormal)|aura]] with their third eye generally associate indigo, in auras, with an interest in [[religion]] or with intense [[spirituality]] and intuition. [[Indigo children]] are said to have predominantly indigo auras. People with indigo auras are said to be in occupations such as [[computer analyst]], [[Animal husbandry|animal caretaker]], and [[counselor]].<ref> Oslie, Pamalie ''Life Colors: What the Colors in Your Aura Reveal'' Novato, California:2000--New World Library Indigo Auras: Pages 161-174 </ref>
'''[[Sociology]]'''
* Indigo was the color worn by the [[Dalit]]s ([[Untouchable (social system)|Untouchables]]) in [[India]] before their [[pariah]] status was made [[illegal]]. If those of the higher [[caste]]s touched any indigo object, they had to perform a [[ritual]] expiation. <ref> Varichon, Anne Colors:What They Mean and How to Make Them New York:2006 Abrams Page 171 </ref>
'''[[Nomenclature]]'''
* India is believed to be the oldest center of indigo dyeing in the Old World. It was a primary supplier of indigo to Europe as early as the Greco-Roman era. The association of India with indigo is reflected in the Greek word for the dye, which was indikon. The Romans used the term indicum, which passed into Italian dialect and eventually into English as the word indigo.
== See also ==
* [[List of colors]]
* [[Indigo dye]]
* [[Indiglo]], a brand name for a method of [[electroluminescence]] technology
==References==
{{reflist}}
{{Shades of blue|Indigo}}
{{Shades of violet}}
{{EMSpectrum}}
[[Category:Optical spectrum]]
[[an:Morau]]
[[ay:K'ulli]]
[[map-bms:Nila]]
[[da:Indigo]]
[[de:Indigo (Farbe)]]
[[es:Añil]]
[[eo:Indigo]]
[[fr:Indigo]]
[[gl:Anil]]
[[id:Nila]]
[[it:Indaco]]
[[he:אינדיגו]]
[[sw:Nili]]
[[lt:Indigas]]
[[nl:Indigo (kleur)]]
[[ja:インディゴ]]
[[no:Indigo]]
[[pl:Indygo]]
[[pt:Anil]]
[[ro:Indigo]]
[[qu:Tinaku llimphi]]
[[ru:Индиго (цвет)]]
[[simple:Indigo]]
[[sl:Indigo]]
[[fi:Indigo]]
[[sv:Indigo (färg)]]
[[vi:Chàm]]
[[zh:靛色]]