Is Indigo a real colour?

Question

The reason I am asking this is that I have read that Newton, when he spilt white light and recombined it, was influenced by his mystical/alchemical background into wanting 7 colours to the rainbow (human spectrum) because of the alchemical significance of 7, so invented the colour indigo. Others claim that some humans can actually see this colour. What do you reckon?

Answer 1

We can see indigo but it is not a primary color in our visual system. Newton could have defined the rainbow as having fewer or more colors and may well have been inclined toward 7 for mystical reasons.

Now, purple by contrast is a "pigment of our imagination." It is what our brain makes up when the two opposite ends of the spectrum are mixed. You can't build a purple laser because there is no monchromatic light that corresponds to it.

Aloha

Answer 2

Yes, but we don't often see it for 2 reasons.
1. Only very hot objects (such as the sun) produce radiation towards the violet end of the spectrum.
2. Such short wavelengths are a) absorbed by water in the air (e.g. the raindrops that cause the rainbow) and b) scattered by particles in the air (hence why the sky is blue and a setting/rising sun appears red/orange)
Or is that 3 reasons?

Answer 3

well it is definitely a very subjective are that has been dominated by newtons opinion, it all comes down to whether you think of indigo and violet as a shades of purple or colours in there own right.
The fact that we even describe something as purple and not either indigo or violet says to me that there is only 6 colours of which there are many shades.

Answer 4

Yes, it's real. You can see it and differentiate it by eye from the other shades of purple. You can measure it with a spectrophotometer.

That having been said, the rainbow is a continuous gradient from about 400 nanometers to about 700 nanometers in wavelength. It would be possible to divide it into any number of colors, from 2 to 200 or more.

Answer 5

Every colour has a different wave length and Newton's prism with its impurities would not would not be able to show them.
Dr Angstrom went further and created a scale for measuring this, and to me this analysis clearly shows that sound and light are related on the same wave form but of course the frequency is lower.
Some humans actually see colours in sound and 'middle C' for instance isn't that note over the keyhole but a colour when played.
Lots feel warmth or coldness in a note too so if this is your interest who knows?
You might take things further.

Good Luck.

Answer 6

yes, it is this color:

javascript: void ( document.bgColor = 'indigo' )
OPEN A NEW IE (OR FIREFOX'S) WINDOW AND COPY THE LINES ABOVE AND PASTE IT ON YOUR BROWSER'S ADDRESS BAR.

In case you are concerned on what you've just done, you're actually running a javascript code that would change your current page's background color into a color indicated on the single quote. The color inputs may be words (like red, orange, indigo, etc) or HTML color code. Not all colors have names, and some names may not display correctly. This script wouldn't work on websites that have background images (like Yahoo Answer), and so you should try it on a new browser windows (press Ctrl+N on IE) and paste it on the address bar. On Firefox, this script wouldn't run on empty browser screen, so you should go to a website, http://www.google.com works as their page don't have background image.

Answer 7

Yes.

The plany 'indigofera tinctoria' was originally domesticated in India, where it is mentioned in manuscripts dating from the 4th century BC. It was recognised as a valuable blue dye by most early explorers of that region. The Venetian explorer Marco Polo described in detail the Indian indigo industry and by the 11th century, Arab traders had introduced indigo to the Mediterranean region, where it replaced their native blue dye plant, woad (Isatis tinctoria).

Answer 8

real colour:

Indigo (or spectrum indigo) is the color on the spectrum between 440 to 420 nanometres in wavelength, placing it between blue and violet. It is a pure chroma on the color wheel between blue and violet. Light that is produced by mixing mostly blue light with some red light is how indigo is produced from two of the three additive primary colors

Answer 9

Yes it's real. It's not primary but it's one of the 7 that my high school physics taught us to remember via the acronym Roy G. Biv.
Red
Orange
Yellow
Green
Blue
Indigo
Violet

And I remember 44 years later.

Answer 10

yes it is it's in the colours of the rainbow= red orange yellow green blue indigo violet (in that order)