Or "Indigo: Absurd Liberal Myth!"
"Indigo is simply an abomination" - mauler
"A careful reading of Newton's work indicates that the color he called indigo, we would normally call blue; his blue is then what we would name blue-green or cyan." -Gary Waldman
Believe it or not, one of the most persistent conversations had in our household was over colour. Christine
was an artist, came from artist stock. She had boxes of crayons and coloured pencils with a range the like of which I had never seen. Who knew there were so many bloody colours, and above all, who knew that every one had a name
? She (or Tess) would take great delight in describing an item of clothing in front of me, only to have me decline the word "aqua" or "teal" in favour of more prosaic descriptors.
I also remember quite an argument breaking out when I was a small wertperch and describing a recently-granted present of a new sweater. When I called it "blue", my mother was shocked that I would describe it so. "Turquoise", she would say. "Green" was my father's vote. I was beaten for my wicked ways.
As a child, I certainly had issues with the names of coloured pencils and crayons - "flesh" as a colour disturbed me greatly - after all, who but a Jeffrey Dahmer would need a flesh-coloured crayon? "Why not 'skin'?" I would ask before the inevitable beating from my teacher.
For me, there were at the time just nine colours that I was prepared to recognise and name: firstly, Red, Orange, Yellow, Green, Blue, Violet. The colours of the rainbow, obviously. Minus indigo, which Newton threw in for good measure. Then brown, the colour of good mud, and poop. Finally, black and white. A little more recently, I have been forced to agree that pink is also a valid colour, largely because "light red" doesn't cover it. Ten colours I will have, and variations of "light", "dark" and possibly "dirty".
This resulted in great consternation in the rest of the family. The womenfolk teased me about my inability to recognise the difference between say turquoise and sea-green, and Christine would give me shit about how black and white were not colours in the first place. I would stand my amused ground in the face of this and then nod sagely as she elucidated at great length.
Some Cultural Observations
I remember being told that at one time there was no German name for the colour orange; German people just called it "red"¹. Well, the word "orange" was drawn from the fruit, and my guess is that they were just not that common in Northern Europe at the time, hence no word for the colour, possibly in any Northern European language.
Whether or not that's true, there are differences between various nations on naming colours. For a long time, the Japanese certainly had no word for orange. Some countries in the East (The BBC cites Vietnam and Korea as examples) do not differentiate between blue and green. The Dugum Dani people of New Guinea (again, from Aunty Beeb) have just two colour names, basically describing items as light or dark. Black and white, if you will.
Men and women certainly seem to have differing views. Randall Munro of xkcd fame recently had a survey on his website to investigate how people identified colour. The results were interesting. Men tended to be less precise than women, who used more descriptive terms to define colour. The link below makes interesting reading, is both informative and highly entertaining. Adjectives like "dusty teal" and "blush pink" were more popular with the women, "puke" and "penis" the more masculine colours.
Others suggest that women are better at colour than men, and that it's genetic. "Five- and six-year-old girls are better at naming colors than boys, and grown men are not as good at color-naming compared to women." This site suggests that some women have not three types of receptor cones in their eyes, but four. This suggestion, that some women possess tetrachromatic vision is not new, but thus far, I am not convinced by this.
Colour-blindness is more common in men than women, too. Perhaps that might explain this discrepancy, but I still prefer to think that we are just the more pragmatic sex.
Back to "Indigo"
The human eye is apparently "somewhat insensitive to hue changes in the wavelengths between blue and violet". Newton also admitted some difficulty in identifying colours, and indeed, in his famous experiments with prisms and the visible light spectrum, had a friend mark the delineations between the differing colours.
It seems that he also wanted there to be seven colours, possibly because he wanted to link to the seven notes of the major scale, possibly also because seven is viewed by some as representing Biblical perfection or completeness.
Certainly, after orange, the spread of the so-called indigo takes the least proportion of the spectrum in his diagrams. Newton, I'll give you orange, but the other? You can keep it.
So my colours, by popular request: Red, Orange, Yellow, Green, Blue, Purple, Brown, Black, White, Pink. Okay, eleven if I include grey. And I was just kidding about the beatings.
Responses From Readers
¹ DonJaime says: "German has a word for orange, which is 'orangenfarbig'. Before oranges, orange was seen as a kind of yellow, rather than red."
mauler adds: "I agree with your worldview on colors. What always bothered me about indigo was that it is not elegant to have  colors. You have 3 "primary" colors" red, blue, and yellow, and then you have 3 other colors that are mixes of two primaries: orange, green, and purple. That is so elegant. If you randomly have indigo between blue and purple, than you'd need to make up 5 other random colors between purple and red, orange and yellow, orange and red, green and yellow, and green and blue. Indigo is simply an abomination.
Maevwyn responds: I went to a fascinating lecture some years back on colour perception - apparently the eye and brain can distinguish between shades of colour much more finely than language does; even people who use a very small number of colour words can visually differentiate almost infinite shades of colour. One wonders if the difference between the sexes also holds true in languages that have a much more restricted vocabulary for colours than English does? English, for whatever reason, seems to be overrun with words for colours - I can't, for example, think of any real equivalent for "teal" or "maroon" in French.
Wikipedia on indigo
Wikipedia on tetrachromats
His and hers colours