Color Vision: Feynman's Physics Explained

Feynman Vol I8-9

Color is not in the light itself — it is in your eyes and brain. Your retina holds three kinds of cone cells, each most sensitive to a different range of wavelengths, roughly red, green, and blue. Any color you see is your brain's reading of the relative strengths of those three signals. That is exactly why a screen can make almost any color from just red, green, and blue light.

The big idea

Color is your brain's interpretation of three kinds of signal.

Think about it

A screen only emits red, green, and blue. How does it convince you that you're seeing yellow or pink?

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