Counter intuitive paint mixing.

Astro Pen

Write now.
Jan 24, 2020
Wales UK
Beginners quite reasonably reply "yellow and blue" if you ask them how to mix green. Well yes it will, but if you want an altogether more subtle green, try yellow and black.

Likewise when you think, "How do I mix turquoise or teal?", white isn't the first thing to pop into your head.
Someone said to me the other day (we were talking about the challenge of colour-matching black) that there is no such thing as black paint (unless you include whatshisname's venta black) it's likely to be a very dark green or very dark blue.

The other thing I remember about mixing colour is that opposites on the colour wheel are good for lightening/darkening colours, so purple is good for yellow, red for green etc.
In my Painting I class, the professor started us off with a limited colour palette instead of full colour so we'd better understand how to mix and shade. For our first assignment, we were only allowed to use one primary colour plus black and white; second assignment he expanded that to complimentary colours plus black and white. An interesting thing about mixing compliments is that it results in brown and each set of compliments makes an entirely different shade of brown.
More on colour mixing. Green light and red light make yellow.
Maybe it shines a little tangential light on this Van Gogh quote?
"There is no blue without yellow and without orange, and if you put in blue, then you must put in yellow, and orange too, mustn't you? Oh well, you will tell me that what I write to you are only banalities."