AKSHULKEH

But actually for real, red + blue = sad poopy purple/kinda maroon.

Teachers have been teaching kids outdated crap based on colour theory from a zillion years ago when they didn't have synthetic pigments

Have you ever heard of CMYK? Cyan, magenta, and yellow are the actual primary colours for pretty much everything the average person would be doing. Black is used to make stuff darker and we will just ignore it (RGB is light and a whole other thing.)

Mixing different portions of any TWO of these three colours gets you nice bright colours. Adding the third brings the colour to a more poopy place. Mixing them equally makes neutral grey.

• 1 cyan + 2 magenta = purple
• 2 cyan + 1 magenta = blue
• 1 yellow + 2 magenta = red
• 2 yellow + 1 magenta = orange
• 1 cyan + 2 yellow = green
• 2 cyan + 1 yellow = turquoise

So red + blue = maroon because

• 2 cyan + 1 magenta = blue
• 1 yellow + 2 magenta = red
• =
• 3 magenta + 2 cyan + 1 yellow = poopy magenta-heavy purple/ maroon

Thanks for attending my TedTalk

[ if your interested in the extended-cut RGB-edition of my TedTalk:

CMYK is subtractive colour theory, because you're using pigments that absorb light and therefore subtract light/colour from what you see.

RGB is additive colour theory, because you're adding light to produce a colour.

Red-yellow-blue makes no sense and should be completely ignored by anyone with more than two brain cells. Teach your kid that their teacher was wrong.

RGB is how screens (TV, monitors, phones, etc) work.

• 1 red + 2 green = yellow
• 2 red + 1 green = orange
• 1 green + 2 blue = turquoise
• 1 green + 1 blue = cyan
• 1 red + 2 blue = Indigo
• 2 red + 1 blue = magenta

If you're a giant colour nerd and are interested in getting good colour from computer screens, you'll never be truly satisfied, because RGB actually cannot produce a good purple, and when you look at colour space reviews, you can see where they're all lacking, no matter how much you spend. Buy yourself a high quality IPS screen. AMOLED isn't great for colour and tends to oversaturate instead of looking realistic. TFT is downright tragic.

Thanks for reading the extended edition]

[you want part three? PURPLE DOESN'T EXIST. Yup. "Purple is your brain, making shit up," she typed, from her phone's purple keyboard.

Our eyes are also RGB, like screens. When we see colours, our brains process them by getting signals from separate red, green, and blue receptors.

Colours are visible wavelengths of light that are on a spectrum. In humans, the visible spectrum goes from Red (1) to green (2) to blue (3). The three receptors are triggered in varying amounts by different colours and our brain mixes them together to make all the other colours.

When we see purple, our red and blue receptors are triggered, so our brains say, "Fun colour mixing time! So red is at one end, and blue is at the other, so half way between is green. I see green. Wait. The green receptor isn't triggering, so it can't be green? But half way between red and blue IS green but it's also NOT-green? This is too much to deal with, so I'll just make up some reddish bluish nonsense and call it purple"

https://www.zmescience.com/science/color-purple-non-spectral-feature/ <- more sciency answer ]

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In summation, this punchline is valid.