Request by one of my watchers, who asked me about my color choices when painting skin.
Even though I haven't been uploading my commissions lately except to their owners, I think maybe other people will find this useful.
Notice that when I blend the outcome is different than the actual color selection (the colors I pick when I use watercolor or airbrush like tool).
When I'm only using hard brush like pen, I will mix the color optically, but it's easier to explain the way I do this using the "true" colors I'm mixing together in my head. So you could mix it together on a separate layer and eyedrop selection from that if you want.
Hope this is useful even though it's more notes than a tutorial. I would like to make a color theory tutorial eventually... that is really a tutorial.
And you can use this for any digital media and any style really.