Spaced Ranger said:

Unless you are merging frames from different sources (for a particular reason), you will get nothing more than if you adjust that single frame.

Hey Spaced Ranger I've found making one frame with the contrast set far apart and one with the contrast in the mid range and layering as transparencies then I get a composite spread of the different information I could'nt get from one set of settings on one frame. Not entirely clear on how it works - I only know that I can't duplicate the results without layering with the program I have. I agree using references and matching the data would be a much less haphazard and more true way of approaching this to my guesswork.