Indigo
From Wikipedia, the free encyclopedia
- This article is about the color. For other uses, see Indigo (disambiguation).
Indigo (or spectral indigo) is the color on the spectrum between 440 and 420 nanometres in wavelength, placing it between blue and violet. Indigo and violet are different from purple (as defined by chromaticians [color scientists]) which does not exist on the electromagnetic spectrum and which can be achieved using additive primary colors by mixing blue light with a red light.
One can see spectral indigo by looking at the reflection of a fluorescent tube in a non-recordable 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), as is visible on the fluorescent lamp spectrum.
#6600FF
Indigo
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[edit] Distinction between four shades of indigo
Like many other colors (orange and violet are the most well-known), indigo gets its name from an object in the natural world—the plant named indigo once used for dyeing cloth (see also Indigo dye).
The color electric indigo is an approximation of spectrum indigo is the color indigo as it looks reproduced on a computer screen--it is the color between the web color blue and the 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 is the color indigo that is usually reproduced in pigments and colored pencils. (Electric indigo can be reproduced approximately in pigments, but it requires adding some white pigment to pigment indigo.)
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 referring to the color Indigo it is always necessary to specify which of the four colors all called indigo you are referring to: the color electric indigo, the color blue-violet (deep indigo), the color pigment indigo, or the color indigo dye (they are four entirely separate and distinct colors).
[edit] Electric indigo
| Electric Indigo | ||
|---|---|---|
| — Color coordinates — | ||
| Hex triplet | #6600FF | |
| RGBa | (r, g, b) | (102, 0, 255) |
| HSV | (h, s, v) | (264°, 100%, 100%) |
| a: Normalized to [0–255] (byte) | ||
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 and spectrum blue as can be seen in the color bands displayed below. This color is the approximation of spectrum indigo on a computer screen. It is impossible to represent spectrum indigo exactly on a computer screen, because true spectrum indigo is outside the gamut of the CIE chromaticity diagram, but electric indigo is a close approximation.
In the psychedelic 1960s, electric indigo color would have been approximated by mixing some fluorescent magenta pigment with a larger amount of fluorescent blue pigment.
Indigo is neither an additive primary color nor a subtractive primary color. It was named and defined by Isaac Newton when he divided up the optical spectrum (which is a continuum of frequencies). He specifically named seven colors primarily to match the seven notes of a western musical scale, because he believed sound and light were physically similar, but also to link colours with the (known) planets, days of the week, and other lists that had seven items.
The human eye is relatively insensitive to indigo's frequencies, and some otherwise well-sighted people cannot distinguish indigo from blue and violet. For this reason some commentators including Isaac Asimov have suggested that indigo should not be regarded as a color in its own right but merely as a shade of blue or violet.
Others continue to accept it as it has been accepted traditionally as one of the major colors of the spectrum along with red, orange, yellow, green, blue, and violet. By looking at the color band comparison chart below of the three colors blue, indigo, and violet, anyone with normal color vision can easily see that all three of these colors are quite distinct.
Of all the pure chromas, indigo has what chromaticians call the highest value, i.e., indigo is intrinsically the darkest of the colors on the color wheel, just as yellow has the lowest value of all the colors on the color wheel, i.e., yellow is the lightest pure chroma on the color wheel.
[edit] Deep indigo (web color blue violet)
| BlueViolet | ||
|---|---|---|
| — Color coordinates — | ||
| Hex triplet | #8A2BE2 | |
| RGBa | (r, g, b) | (138, 43, 226) |
| HSV | (h, s, v) | (271°, 81%, 89%) |
| a: Normalized to [0–255] (byte) | ||
At left 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.
[edit] Pigment indigo (web color indigo)
| Pigment Indigo | ||
|---|---|---|
| — Color coordinates — | ||
| Hex triplet | #4B0082 | |
| RGBa | (r, g, b) | (75, 0, 130) |
| HSV | (h, s, v) | (275°, 100%, 51%) |
| a: Normalized to [0–255] (byte) | ||
The color box at right displays the web color Indigo which is equivalent to pigment indigo, i.e., the color indigo as it would be reproduced by artist's paints as opposed to the brighter indigo above (electric indigo) that it is possible to reproduce on a computer screen.
Pigment indigo is the color you would get if you mixed about 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 pencils in the 1950s. By the 1970s, 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.
[edit] Indigo dye
| Indigo dye | ||
|---|---|---|
| — Color coordinates — | ||
| Hex triplet | #1A5798 | |
| RGBa | (r, g, b) | (17, 80, 147) |
| HSV | (h, s, v) | (275°, 50%, 51%) |
| a: Normalized to [0–255] (byte) | ||
Displayed at right is the color indigo dye. This color sample was taken directly from the indigo dye color swatch in the Wikipedia Indigo dye article. A vat full of indigo dye would be a much darker color, approximating the web color midnight blue.
[edit] Comparison of blue, indigo, and violet
Note: The spectrum colors can only be approximated on a computer screen due to the color limitations of the color gamut reproducible within the CIE chromaticity diagram.
- blue (Hex: #0000FF) (RGB: 0, 0, 255)
- electric indigo (Hex: #6600FF) (RGB: 102, 0, 255)
- electric violet (Hex: #8B00FF) (RGB: 139, 0, 255)
[edit] Shades of indigo color comparison chart
- lavendula (Vietnamese lavender) (pale indigo) (Hex: #E6E6FA) (RGB: 230, 230, 250)
- periwinkle (lavender blue) (pastel indigo) (Hex: #CCCCFF) (RGB: 204, 204, 255)
- light indigo (Hex: #B198FF) (RGB: 177, 147, 255)
- brilliant indigo (Hex: #9877FF) (RGB: 147, 119, 255)
- steel blue (Hex: #4682B4) (RGB: 70, 130, 180)
- indigo dye (Hex: #1A5798) (RGB: 17, 80, 147)
- bright indigo (Crayola indigo) (Hex: #4F69C6) (RGB: 79, 105, 198)
- INDIGO (electric indigo) (Hex: #6600FF) (RGB: 102, 0, 255)
- deep indigo (web color blue-violet) (Hex: #8A2BE2) (RGB: 138, 43, 226)
- pigment indigo (web color indigo) (Hex: #4B0082) (RGB: 75, 0, 130)
- Persian indigo (Hex: #32127A) (RGB: 50, 18, 122)
- midnight blue (Hex: #003366) (RGB: 0, 51, 102)
- Prussian blue (Berlin blue) (Hex: #003153) (RGB: 0, 49, 83)
- dark indigo (Hex: #310062) (RGB: 49, 0, 98)
[edit] Indigo in culture
Food
- The outer skin of most varieties of eggplant is colored pigment indigo.
- So called "purple" carrots and potatoes are actually colored pigment indigo.
Midwifery
- In the ancient Maya civilization indigo was the one color that was recognized for its soothing effect on pregnant women and their unborn children. Pregnant women often wore this color in order to protect themselves and their child from danger and to ensure a safe and successful delivery.
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 related to intuition and knowledge.
Parapsychology
- Psychics who claim to be able to observe the aura with their third eye generally associate indigo, in auras, with intense spirituality and intuition. Indigo children are said to have predominately indigo auras.
Technology and video games
- One color of the Apple iMac G3 is indigo.
- In keeping with a color theme for towns and cities in Pokémon's Kanto region, the location containing the Elite Four is 'Indigo Plateau.
[edit] See also
- List of colors
- Indigo dye
- Indiglo, a brand name for a method of electroluminescence technology
| Shades of violet | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Amethyst | Cerise | Eggplant | Fuchsia | Heliotrope | Indigo | Lavender | Lavender blush | Lilac | Magenta | Mauve | Mountbatten pink |
| Orchid | Persian indigo | Purple | Red-violet | Sangria | Thistle | Violet | Violet-eggplant | Wisteria | Rose | Lavender rose | Lavender gray |
| Shades of violet without swatches | |||||||||||
| Iris | Palatinate | Purpure | |||||||||
| The Electromagnetic Spectrum (Sorted by wavelength, short to long) |
|
| Gamma ray | X-ray | Ultraviolet | Visible spectrum | Infrared | Terahertz radiation | Microwave | Radio waves | |
| Visible (optical) spectrum: | Violet | Blue | Green | Yellow | Orange | Red |
|---|---|
| Microwave spectrum: | W band | V band | K band: Ka band, Ku band | X band | C band | S band | L band |
| Radio spectrum: | EHF | SHF | UHF | VHF | HF | MF | LF | VLF | ULF | SLF | ELF |
| Wavelength designations: | Microwave | Shortwave | Mediumwave | Longwave |
