Editing Indigo (section)

== Distinction among tones of indigo ==
{{Unref section|date=March 2025}}
Like many other colors ([[Orange (colour)|orange]], [[Rose (color)|rose]], 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 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 from either spectrum indigo or pigment indigo. This is the actual color of the dye. A vat full of this dye is a darker color, approximating the web color [[midnight blue]].

The color "electric indigo" is a bright and [[colorfulness|saturated]] color between the traditional indigo and violet. This is the [[lightness|brightest]] color indigo that can be approximated on a computer screen; it is a color located between the (primary) blue and the color [[Violet (color)#Electric violet|violet]] of the RGB color wheel.

The web color blue violet or deep indigo is a tone of indigo brighter than pigment indigo, but not as bright as electric indigo.

Listed below are several indigo hues, some of which have included the word "indigo", with the adoption of [[HTML color names]] in the [[World Wide Web]] era.

=== Indigo dye color ===
{{Main|Indigo dye}}
{{infobox color
|title=Indigo Dye
|hex=00416A
|source=[[desktoppub.about.com]]<ref name="electric-coords" />
|isccname=Deep blue}}
''Indigo dye'' is a greenish dark blue color, obtained from either the leaves of the tropical Indigo plant (''[[Indigofera]]''), or from woad (''[[Isatis tinctoria]]''), or the Chinese indigo (''[[Persicaria tinctoria]]''). Many societies make use of the ''[[Indigofera]]'' plant for producing different shades of blue. Cloth that is repeatedly boiled in an indigo dye bath-solution (boiled and left to dry, boiled and left to dry, etc.), the blue pigment becomes darker on the cloth. After dyeing, the cloth is hung in the open air to dry.

A Native American woman described the process used by the [[Cherokee Indians]] when extracting the dye:
<blockquote>We raised our indigo which we cut in the morning while the dew was still on it; then we put it in a tub and soaked it overnight, and the next day we foamed it up by beating it with a gourd. We let it stand overnight again, and the next day rubbed [[tallow]] on our hands to kill the foam. Afterwards, we poured the water off, and the sediment left in the bottom we would pour into a pitcher or crock to let it get dry, and then we would put it into a poke made of cloth (i.e. sack made of coarse cloth) and then when we wanted any of it to dye [there]with, we would take the dry indigo.<ref>{{Citation |contribution=History of the Cherokees, 1830–1846 |title=Chronicles of Oklahoma |last1=Knight |first1=Oliver |publisher=Oklahoma Historical Society|place=Oklahoma City|year=1956–57|page=164|oclc=647927893 |language=en }}</ref><ref>{{cite book|author-last=Foreman|author-first=Grant|title=The Five Civilized Tribes|publisher=University of Oklahoma Press|location=Norman|year=1934|page=283|language=en|url=https://books.google.com/books?id=gGtLnSkqkekC&q=We+raised+our+indigo&pg=PA283|isbn=978-0-8061-0923-7|access-date=1 November 2020|archive-date=30 June 2023|archive-url=https://web.archive.org/web/20230630145344/https://books.google.com/books?id=gGtLnSkqkekC&q=We+raised+our+indigo&pg=PA283|url-status=live}}</ref></blockquote>

In [[Sa Pa]], Vietnam, the tropical Indigo (''Indigo tinctoria'') leaves are harvested and, while still fresh, placed inside a tub of room-temperature to lukewarm water where they are left to sit for 3 to 4 days and allowed to ferment, until the water turns green. Afterwards, crushed limestone ([[pickling lime]]) is added to the water, at which time the water with the leaves are vigorously agitated for 15 to 20 minutes, until the water turns blue. The blue pigment settles as sediment at the bottom of the tub. The sediment is scooped out and stored. When dyeing cloth, the pigment is then boiled in a vat of water; the cloth (usually made from yarns of [[hemp]]) is inserted into the vat for absorbing the dye. After hanging out to dry, the boiling process is repeated as often as needed to produce a darker color.
{{Clear}}

=== Indigo (color wheel) ===
{{infobox color
| title=Indigo (color wheel)
| hex=4000FF
| hexref=<ref name="electric-coords">{{cite web |title=What Color is Indigo? |url=http://desktoppub.about.com/od/choosingcolors/f/What-Color-Is-Indigo.htm |url-status=dead |date=16 December 2014 |archive-url=https://web.archive.org/web/20151226130706/http://desktoppub.about.com/od/choosingcolors/f/What-Color-Is-Indigo.htm |archive-date=26 December 2015}}</ref>
|isccname=Vivid purplish blue}}

In a [[RGB color space]], "Indigo(color wheel)" is composed of 25.1% [[red]], 0% [[green]] and 100% [[blue]]. Whereas in a CMYK color space, it is composed of 74.9% [[cyan]], 100% [[magenta]], 0% [[yellow]] and 0% [[black]]. It has a hue angle of 255.1 degrees, a saturation of 100% and a lightness of 50%. Indigo(color wheel) could be obtained by blending [[Violet (color)#Violet(color wheel)|violet]] with [[blue]].
{{Clear}}

=== Electric indigo ===
{{infobox color
| title=Electric Indigo
| hex=6F00FF
| hexref=<ref name="electric-coords"/>
|isccname=Vivid purplish blue}}

"Electric indigo" is brighter than the pigment indigo reproduced above. When plotted on the [[CIE chromaticity diagram]], this color is at 435 nanometers, in the middle of the portion of the spectrum traditionally considered indigo, i.e., between 450 and 420 nanometers. This color is only an approximation of spectral indigo, since actual spectral colors are outside the [[gamut]] of the [[sRGB]] color system.
{{Clear}}

=== Deep indigo (web color blue-violet) ===
{{infobox color
|title=Blue-Violet
|hex=8A2BE2
|source=[[Web colors#X11 color names|X11]]
|isccname=Vivid violet}}

At right is displayed the web color "blue-violet", a color intermediate in brightness between electric indigo and pigment indigo. It is also known as "deep indigo".
{{Clear}}

=== Web color indigo ===
{{infobox color
|title=Web color Indigo
|hex=4B0082
|source=[[colorhexa.com]]<ref>{{Cite web|url=https://www.colorhexa.com/4b0082|title=Indigo / #4b0082 hex color|website=ColorHexa}}</ref>
|isccname=Dark violet}}

{{infobox color
|title=Web safe Indigo
|hex=330099
|source=[[rgbcolorcode.com]]<ref>{{Cite web|url=https://rgbcolorcode.com/color/330099|title=#330099 🎨 RGB Color Code|website=rgbcolorcode.com}}</ref>
|isccname=}}

The color box on the right{{which?|reason=There are two colors under this heading and nothing discusses which one is actually web indigo|date=March 2025}} displays the web color indigo. Its hue is closer to violet than to indigo dye for which the color is named.
{{Clear}}

=== Tropical indigo ===
{{infobox color
|title=Tropical Indigo
|hex=9683EC
|source=Gallego and Sanz<ref>Gallego, Rosa; Sanz, Juan Carlos (2005). ''Guía de coloraciones'' (Gallego, Rosa; Sanz, Juan Carlos (2005). ''Guide to Colorations'') Madrid: H. Blume. {{ISBN|84-89840-31-8}}</ref>
|isccname=Vivid violet}}

'Tropical Indigo' is the color that is called ''añil'' in the ''Guía de coloraciones'' (Guide to colorations) by Rosa Gallego and
Juan Carlos Sanz, a color dictionary published in 2005 that is widely popular{{According to whom?|date=March 2025}} in the [[Hispanophone]] realm.
{{Clear}}

===Imperial blue===
{{infobox color
| title=Imperial Blue
| hex=002395
| isccname=Vivid blue}}
{{Clear}}