Indigo (color)

Indigo
A piece of indigo plant dye from India, about 6 cm (2.5 in) square
Wavelength	450–420(disputed) nm
Color coordinates
Hex triplet	#4B0082
sRGBB  (r, g, b)	(75, 0, 130)
CMYKH   (c, m, y, k)	(42, 100, 0, 49)
HSV       (h, s, v)	(275°, 100%, 51%)
Source	HTML/CSS
B: Normalized to [0–255] (byte) H: Normalized to [0–100] (hundred)

Electric Indigo
Color coordinates
Hex triplet	#6F00FF
sRGBB  (r, g, b)	(111, 0, 255)
CMYKH   (c, m, y, k)	(57, 100, 0, 0)
HSV       (h, s, v)	(266°, 100%, 100%)
Source	[1]
B: Normalized to [0–255] (byte) H: Normalized to [0–100] (hundred)

Blue-Violet
Color coordinates
Hex triplet	#8A2BE2
sRGBB  (r, g, b)	(138, 43, 226)
CMYKH   (c, m, y, k)	(63, 81, 0, 0)
HSV       (h, s, v)	(271°, 81%, 89%)
Source	X11
B: Normalized to [0–255] (byte) H: Normalized to [0–100] (hundred)

Indigo
Color coordinates
Hex triplet	#4B0082
sRGBB  (r, g, b)	(75, 0, 130)
CMYKH   (c, m, y, k)	(42, 100, 0, 49)
HSV       (h, s, v)	(275°, 100%, 50%)
Source	X11
B: Normalized to [0–255] (byte) H: Normalized to [0–100] (hundred)

Tropical Indigo
Color coordinates
Hex triplet	#9683EC
sRGBB  (r, g, b)	(150, 131, 236)
CMYKH   (c, m, y, k)	(48, 51, 0, 0)
HSV       (h, s, v)	(251°, 44%, 93%)
Source	Gallego and Sanz
B: Normalized to [0–255] (byte) H: Normalized to [0–100] (hundred)

Indigo is a deep and bright color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine. It is traditionally regarded as a color in the visible spectrum, as well as one of the seven colors of the rainbow: the color between blue and violet; however, sources differ as to its actual position in the electromagnetic spectrum.

The color indigo is named after the indigo dye derived from the plant Indigofera tinctoria and related species.

The first known recorded use of indigo as a color name in English was in 1289.

Species of Indigofera were cultivated in Peru, India, East Asia and Egypt in antiquity. The earliest direct evidence for the use of indigo dates to around 4000 BCE and comes from Huaca Prieta, in contemporary Peru.Pliny mentions India as the source of the dye, imported in small quantities via the Silk Road. The Greek term for the dye was Ἰνδικὸν φάρμακον ("Indian "), which, adopted to Latin as indicum and via Portuguese gave rise to the modern word .El Salvador has lately been the biggest producer of indigo.

Indigo was actually a plant that got its name because it came from the Indus Valley, discovered some 5,000 years ago, where it was called nila, meaning dark blue. And by the 7th Century BC, people starting using the plant as a dye — the Mesopotamians were even carving out recipes for making indigo dye onto clay tablets for record-keeping. By 1289, knowledge of the dye made its way to Europe, when the Venetian merchant traveler Marco Polo reported on it.