JanB1 wrote:Hmm...I think most of us learned the RYB system in school.
RYB is not a system - it's impossible to make all colours using just red, blue and yellow. (you can, for example, not mix cyan or magenta without using white too, whereas you can mix red by adding yellow and magenta
And when you PAINT stuff, you use the the NCS system that uses white, black, green, yellow, red and blue.
Well, yes and no. First, NCS is not really a colour 'system' (which is why it has 6 colour and not 3), and is more for putting a number on colour perception, not mixing. (as Silver points out above). It's not made to replace CMY, it's made so people can more easily pick a colour for their wall paint, because CMY, while physically correct, is counter-intuitive.
You could, technically, mix every colour using those 6 colours when painting, if you really like mixing instead of painting, but realistically you're gonna have black, white, cyan, magenta, yellow, green, blue, orange and purple at the very least (generally some other tints as well depending on what you paint - landscape painters will have several greens etc) and you mix hues rather than colours.