Tom Blahovic's processing challenge :
Single M31 image on Fuji 800 film
Tom's image as downloaded and resized:
Tom's Image After I Adjusted it in Photoshop
To bring out the galaxy, I increased contrast in the arms while protecting the nucleus from being completely blasted out. My approach (learned from Mike Stecker) was to select the nuclear area with Select/Color Range, feather it, and then do an inverse so that the nucleus was protected and everything else was changeable. Some ruthless application of levels and contrast/brightness worked pretty well to bring up the arms. The colors in the arms were still rather brownish, so I then used Color/Balance to reduce the brown and bring out the blue more. (I think Fuji films are given to a brownish cast.) I tried to reduce the vignetting but with not much success.
Nice image, Tom!