Eli5: How does the colour purple “not exist”?
In: Physics
Our eyes perceive different wavelengths of light as different colors, but that doesn’t mean every color we perceive has its own wavelength. There’s no single wavelength of light that you can create to shine “pure purple light”; rather, we perceive purple when our eyes sense both red and blue light.
Usually, our eyes see loads of different wavelengths and more or less average them out – pure blue and green light together are perceived as yellow, the same as pure light in between those two. But red and blue are on opposite ends of the visible spectrum, and blue + red doesn’t look like the midpoint between them, which would be some shade of green. Instead our eyes perceive red light and blue light together as something else, purple.
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