I've always been baffled by the separation of the visible spectrum into ROYGBIV – red, orange, yellow, green, blue, indigo, and violet. I can see the difference between indigo and violet, but they seem very close. To me, indigo is like blue-green; it doesn't really deserve its own name. If it were up to me, it would simply go red, orange, yellow, green, blue, purple. So I wondered if maybe I'm a little colorblind.
What do you think? Is indigo really so different from blue and violet that it deserves its own color?