I'm not sure what he did, other than the reconstructed flopped half of a portrait (does that make sense?). The lighting is intriguing, and he obviously has applied a combination of techniques to come up w/this look. Someone once showed me this tutorial, which Robin may have taken a similar approach...
http://www.reviewzine.com/photoshop-...ur-photograph/
Have you tried asking him, yet? I noticed he doesn't post what technique he uses when asked directly on his flickr responses. (I wouldn't either, if I worked really hard on a new series, at least not until I was over it and onto the next experiment.)
LF