Here the figures are back-lit. This is rim lighting, although not the most extreme case.

Compare the VSS shader to yours. Because you're not using Blinn, but a Specular node instead, you're not getting the sharp bright specular on the edges. Even with the correct Fresnel (in the middle) its not there, because the Specular node just can't generate that kind of response. The Specular node is a left-over from 1985 and should not have even been included in Poser, in my opinion.

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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)