Indigo
| Indigo Dyers and Colourists | |
|---|---|
| Components | |
| RGB ( r , v , b ) | (47, 0, 127) |
| Hex triplet. | 2F007F |
| CMYK ( c , m , j , n ) | (63%, 100%, 0%, 50%) |
| TSL ( t , s , l ) | (262 , 100%, 25%) |
change  | |
| Indigo Web | |
|---|---|
| Components | |
| RGB ( r , v , b ) | (75, 0, 130) |
| Hex triplet. | 4B0082 |
| CMYK ( c , m , j , n ) | (42%, 100%, 0%, 49%) |
| TSL ( t , s , l ) | (275 , 100%, 25%) |
| change | |
The indigo (from Latin India) is a shade of dark blue.
Summary |
Composition
The true blue indigo (NB1) is originally derived from the woad.
The dye was then synthesized by A. Bayer in 1870 (PB66) after 1897 and marketed by BASF. Unfortunately, not permanent, it fell into disuse.
Today, the color indigo is made from a mixture of blue pigments (ultramarine, phthalo) and black.
The "seventh color" of the rainbow
Indigo is often termed "seventh color" of the rainbow. In reality, this color is not in the spectrum of visible colors. The retina of the eye normal human, if one omits the abnormalities such as blindness or achromatopsia (total absence of color vision), contains three types of cones to collect different colors, each with the maximum response in the wavelengths of the red primary (response to beta-carotene ), the primary green and blue primary. The indigo would theoretically a small part of the visible spectrum but in practice is not in the normal decomposition of light (because it is a dark color).
Some bright colors do not raise any ambiguity. It knows what a red , a yellow or green. The indigo is a color, however ill-defined because of the myth of the seventh color. Supposed to be on the rainbow sky between the blue and violet, it was concluded that indigo should be a precise shade halfway between violet and blue. But the human eye is very sensitive to the nuances in this area of the spectrum and it is very subjective to say that such intermediate shade between blue and violet is classified in the blue or violet in rank. The only reference we have natural indigo dyeing is the dye used to color blue jeans. However, this dye is not nothing but a dark shade of blue.
The indigo was added and virtually invented by Isaac Newton after having decomposed the visible light with a prism (which is obviously a continuum of frequencies and reveals that in fact only 6 dominant colors), the 3 primaries (red, yellow , blue) and 3 secondary or tertiary (orange, green, purple). He consciously determined seven colors to coincide with the 7 planets (then known), 7 days a week, 7 notes of music, and other septenaries held cultural references.
The ambiguity is sustained by the fact that there is a shade of indigo blue purple as defined in the names of colors used in HTML: As the indigo dye is close to the midnight blue # 191970, color "web" # 4B0082, draws more on the purple.
Expressions
- The indigo bunting is a bird of North America , whose male has a plumage blue indigo.
- The term " indigo child "means in the context of a theory new age denounced in France Related articles
References
- Report of the Parliamentary Inquiry Commission on Cults in France , 2006.
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