Want to see something wierd?

Turn off the diffuse calculation altogether, by setting PM:Diffuse Reflectivity to 0. This means that all the remaining light (after the specular reflection is calculated) goes into the SSS calculation. So in this render you can see exactly what the SSS is doing.

Only places where the light is striking the skin at a shallow angle is triggering the SSS layer. Everywhere else is black here. (Excluding the specular reflections, of course.)

What that means is that if you're getting too much red, even on well-lit surfaces pointing at your main light, it's because the color map (texture map) you're using is too red to begin with.

A lot of texture makers include too much red in the texture, basically because it looks better that way if you're not using gamma correction. But with this physically accurate shader, the skin color should actually be the color of parchment paper.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)