Quote - I noticed this for years really. Once you convert a render to greyscale, you see how little contrast survives at rendertime.

Just a thought...have you tried going into the channels and clicking on each of the color plates...r, g, and b? sometimes one of those has more detail or the detail you want than just converting to greyscale :). If you chose one of the channels and delete the other two you may be able to keep more of the details. It's been been my experience that red or blue usually seem to get the closest to what I'm after ;). Then convert that one color to greyscale :). Or you could copy each one, desaturate and then layer them using different layer settings...see what ya get.

Laurie