It is interesting how diverse the colors are in skin tones, I find myself painting green skin very often.
I think photos tend to loose a lot of color difference because as I look at myself in the mirror I see all kinds of colors in my skin tones. Such as blues and green. Try it, just look at the back of your hand in good light, preferably sunlight. You should see, if you’re caucasian, blues, greens, pinks, white, reds, yellows all kinds of colors.
And after writing this I realize that I need to get some good photos of non caucasian models. Sigh… I’m so limited by my ability to gather good reference materials.