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What Does Indigo Mean?

Indigo is a spectral color between blue and violet at about 420 to 450 nanometers (nm) in wavelength.


Today’s color scientists do not often recognize indigo as a separate color division and place it between blue and violet.

Techopedia Explains Indigo

Any wavelength of less than 450 nm is simply referred to as violet. Here are the color frequency wavelengths:

  • Violet 380–450 nm
  • Indigo is about 435 nm
  • Blue 450–475 nm
  • Cyan 476–495 nm
  • Green 495–570 nm
  • Yellow 570–590 nm
  • Orange 590–620 nm
  • Red 620–750 nm

Isaac Newton originally divided the color spectrum into the seven colors: red, orange, yellow, green, blue, indigo, and violet. Although indigo is traditionally one of seven divisions in the optical spectrum, the human eye is relatively insensitive to indigo’s frequencies. In fact, some well-sighted people cannot distinguish indigo from blue or violet.

The color electric indigo is the brightest version of indigo on a computer screen, and is located between Web blue and violet on the RGB color wheel. Deep indigo is another name for the Web color blue/violet, which is brighter than the Web color indigo but not as bright as electric indigo.

Electric indigo may be used as a glow color in computer graphics lighting. It is said to change color from indigo to lavender when blended with white.


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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.