Mike,
I've been scanning some old slides on a flat-bed with VueScan and with an output of DNG-Tif files. The idea being that I can make use of the Q-SE raw image processing features on these files, including noise reduction for the film grain.
I was wondering how Noise Reduction works in this situation as there is no ISO value associated with the image. I cannot see any change to the image whatever the NR setting is used in the preferences.
Perhaps I'm on the wrong tack altogether!
EDIT: just to clarify, VueScan calls them Tiff DNG format and they have a .dng extension. Qimage reads them as a raw file and refine etc. works.

Terry.

Thanks Mike,
I just wondered if there was a work-round. I used the NeatImage route in the end - just to exercise that program a little; Q-SE raw processing is has made it more-or-less redundant. 
Terry