Why are indigo and violet in the rainbow and not just purple? - eviltoast

I always learned “ROYGBIV” as the colors of the rainbow. Red, orange, yellow, blue, indigo, violet.

What’s up with the last two? Isn’t indigo basically just dark blue? Why is it violet and not purple? Can’t it just be “ROYGBP”?

  • snoopen@lemmy.world
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    1 year ago

    Essentially our brain can detect 3 colours separately, red, green and blue.

    Do you have a source for this? I’m pretty sure our brains can detect any arbitrary wavelength within a range. The red green blue thing just happens to be the three colours we can mix to emulate most (but not all) of the frequencies we can detect.

    • DKP@lemmy.world
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      1 year ago

      There are 3 types of cones in the human eye, which reactive to different bands of the spectrum. They peak at approximately red, blue, and green. Our brains are good at combining that information to make it appear seamless. Colorblindness is generally a genetic defect in the production of one or more of those type of cones. https://askabiologist.asu.edu/rods-and-cones