Thanks for your reply. I am using LR3 beta (latest version, Mac). I have been using the noise reduction "detail" sliders, and in luminance noise, the contrast slider as well. While they seem to help in this regard, I am not seeing the type of control over surface vs detail that I have in mind. Perhaps I am missing something because I don't see a lot of change with the detail or contrast sliders—some, just not a lot. I have not found an on-screen mask display if I hold down the option key, as I do in the sharpening sliders. If these sliders are acting as a mask, as the sharpening slider does, I have not yet got the feel for it.
Am I missing something?