Many students of art are interested in the colors used in mixing flesh-tones when painting a portrait.
There are some principles to follow that can simplify the issue. Everything that we paint is red, yellow or blue. Red doesn't always mean a bright cadmium red and yellow doesn't always mean cadmium yellow and blue isn't necessarily any of the blues on the palette. What this means is that red might be terra rosa ( an earth red ); yellow might mean yellow ochre and blue might be gray instead.
So, as a starter, artists must study their model's complexion. How red is it; is it more of a yellow complexion and how cool is it( blue )?
A basic flesh-tone can be made by mixing cadmium red light or vermilion + yellow ochre + a middle gray.( gray is made with ivory black + white ). The gray controls the intensity of the mixture of the red and yellow ochre.. By a middle gray, I mean between light and dark .
More red in this mixture will give a ruddier complexion , more yellow ochre will create a softer , more balanced flesh-tone.
People who have a fair complexion require a different red and a different yellow and I would suggest a warmer gray. So these would be cadmium yellow medium + alizarin crimson + gray ( made with raw umber + white ).
As you build the light on the head , you'll need mixtures ( in the first case ) of cadmium red light ( or Vermilion ) + yellow ochre + white . In the second case , of the fair complexion make a mixture of cadmium yellow medium + alizarin crimson + white to build the lights on the head.
The shadow in each of these cases is the same; a mixture of cadmium red light + cobalt blue . There is more red than blue in this mixture. ( it's a warm violet ).
This is a brief synopsis of colors used in mixing flesh-tones. More information can be found in my free downloadable video as well as my DVD on portrait painting. Click on my Shop for the details.