I have always loved to paint skin! Not only beige and brown but ALL colours reside in the human skin. If you look closer you can see the tip of your finger turn red and the veins on your vrist blue. An olive green reside in the shadow and a shy yellow in the light. The old masters painted skin in thin layers of oil colours (or tempera) that had to dry between the applications. Beginning with the dark blue-green layers they worked themself through the earthy browns and reds towards the light yellow, ocher and white.
Details from some of my own paintings in oil colour: