Your intuition is on the right track, but it works “the other way around”.
RGB are additive primary colours, because the colour you see when you look at something that emits light is the actual colour of the light. And so when you mix two coloured lights, the colours add up (additive colours). And adding every colour gives you white.
CMY are instead subtractive colour, because when you look at something that does not emit light, the colour you see is just the light that bounces off of it, while some colours get absorbed. So when you mix paints, the resulting paint absorbs more colours, and you only see what’s left, so the colours subtract down (subtractive colours). And subtracting everything gives you black.
Your intuition is on the right track, but it works “the other way around”.
RGB are additive primary colours, because the colour you see when you look at something that emits light is the actual colour of the light. And so when you mix two coloured lights, the colours add up (additive colours). And adding every colour gives you white.
CMY are instead subtractive colour, because when you look at something that does not emit light, the colour you see is just the light that bounces off of it, while some colours get absorbed. So when you mix paints, the resulting paint absorbs more colours, and you only see what’s left, so the colours subtract down (subtractive colours). And subtracting everything gives you black.
Oops, you’re right! That’s what I meant to say but I got mixed up