A few facts from the video below, this was all fascinating to me and something I never really knew, did you? So it turns out, the primary colours you're taught in school are more secondary if anything. Red, Blue, and Yello. These are Additive primary colours. While Cyan, Magenta, and Yellow are subtractive. See you're told that you can use RBY to mix and make any other colour you want to. False! RBY should be Red, Blue, and Green! While all 6 (RBGCMY) are technically primary and secondary depending on your terminology, Cyan, Magenta, and Yellow are the true primary colours that you can get any colour from. That's why printers use CMYK because they need to be able to make every colour that you can print.

See with Cyan and Magenta you can make Blue. Yellow and Magenta you can make Red. This is why they can't be primary colours. Another fun fact, Magenta doesn't even exist! It all has to do with your brain and the way that eyes work. It all has to do with the light spectrum and waves. It's very technical and is explained in the video, but basically, your eyes work on the RGB spectrum, if there's a colour between Red and Green it thinks it is Yellow. Between Green and Blue it thinks something like Cyan, but if it thinks it's something between Red and Blue, that's Green, BUT your Green cones aren't reacting so it just makes up this random colour and that's Magenta. Crazy, isn't it? Check out the video below to find out more behind these facts!