How come red & purple are on opposite, far ends of the electromagnetic spectrum, but when mixing colors together in kindergarten, purple is halfway between red & blue?

Question

Shouldn’t common sense dictate that either both be one, or both be the other?

In: 1934

Answer 1

At the time I’m posting this, nobody in the comments properly answered your question.

The trick is that the cells in your eyes that perceive the red wavelength are not working the way that you think.

They perceive mainly red at one end of the light spectrum, but are also slightly sensitive to the very opposite end of the spectrum, beyond blue, that’s why you can perceive indigo there, and your brain perceives it as a mix of blue with a bit of red.

It kinds of gives you the illusion that the spectrum “circles back” to itself.

The purple color is kind of artificially created by the brain.

This article explains it better than me: [https://www.zmescience.com/feature-post/natural-sciences/physics-articles/matter-and-energy/color-purple-non-spectral-feature/](https://www.zmescience.com/feature-post/natural-sciences/physics-articles/matter-and-energy/color-purple-non-spectral-feature/)

[https://cdn.zmescience.com/wp-content/uploads/2021/04/color-cones.png](https://cdn.zmescience.com/wp-content/uploads/2021/04/color-cones.png)