There is method to the DV=1 madness as well. It all has to do with NOT having gamma correction or SSS, so having to do some fakery to perform something that looks more like variations in redness in the skin and also something that does gamma compensation. Most forms of compensation involve adding more light, or reflecting more light. Most forms of skin SSS fakery involve removing some red as a basis (thus a light blue tint), then selectively adding it back in a non-uniform way.

I actually was the person who first posted the blue-red technique, although I later abandoned it for a number of reasons. It can produce a very good look, but only in a very limited range of lighting, and never works when real gamma correction is used. Face_off picked it up and used it in V3 shaders he made for Daz. He used it because it was a fake-sss technique that worked without scripting when moving lights.

Poser Pro did not exist then.

I later developed better ones, but the Daz copycats (vendors who copied the Daz V3 and V4 shader) never picked up on the newer techniques, or they found them too complicated. (The newer techniques require a lot more nodes)

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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)