why purple is on the end of the rainbow/color spectrum

Question

First of all, I don’t understand why indigo and violet are split… why not just call it purple? Ok, not my question.

Colors of the rainbow all make sense to me except purple.

Red – orange – yellow…makes sense that orange is between red and yellow, and it’s the combination of those two primary colors, nice transition

This follows with green, blue. Green is between yellow and blue.

Now… if purple aka indigo and violet are a combination of blue and red, how can it be on the opposite end of red (very different frequency) and outside the frequency range of blue? I would expect a secondary color’s frequency to be between the two primary colors that create it

In: 76

Answer 1

Purple is a special colour, it’s not a pure colour with one frequency, it is a mixture of both red and blue(or indigo or violet).

When you mix these colours from the opposite ends of the spectrum they don’t average out to produce green but the unique colour purple.