this post was submitted on 15 Jul 2023
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Explain Like I'm Five

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54
How do computers make any color using red/green/blue, when paints make every clor using red/yellow/blue?o (wirebase.org)
submitted 1 year ago by [email protected] to c/[email protected]
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Im always confused by RGB. I learned that if you want orange, you mix red and yellow. If you want green, you mix blue and yellow, if you want purple, you mix red and blue.

How is it that computers need green and not yellow?

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[–] [email protected] 29 points 1 year ago

Computer screens emit light, so when your computer shows a green LED next to a red LED, both green and red light wavelengths are sent to your eyes, and your brain interprets this as yellow. This is because your eyes only have red, green, and blue receptors in them, so sending green light mixed with red light is indistinguishable from pure yellow light.

Pigment, instead, works by absorbing light. The trick is that red, yellow, and blue are not the primary colors of light--it's instead Cyan, Magenta, and Yellow (which look similar to Red, Yellow, and Blue). Yellow pigment absorbs blue light, magenta pigment absorbs green light, and cyan pigment absorbs red light. Therefore, if you mix yellow and cyan pigments together, the resulting mixture absorbs the blue AND red light, so green is the only wavelength left that gets reflected back and picked up by your eyes.

I found a video on it that explained this well with a neat diagram: https://youtu.be/YtH9eXWuf3Y?t=44