Anyone ever see anything like this? I need to run some controlled experiments. I can't see any streaking on the negatives (good!). Think it may be the Nikon scanner. (Perhaps) its always the last frame in the negative holder.

Well that sucks, if it's the scanner... do you always get this? If so I would complain to Nikon... almost looks like a chemical stain... like from fixer or developer but since it's a negative scan, obviously it isn't.

Just started noticing it. Since it is (I think) always last frame in the holder, the problem may be light leakage from the next (empty) frame. Nikon gives stern warnings about blocking out empty frames using some particularly inconvenient strips of mylar. This could be why?

I think you do need to do your controlled experiments... although why in the world would you need mylar strips to block out empty frames is beyond me... The Canon scanner I have does not require this and I've never seen anything like this happen to mine...

Try scanning without anything in the neg holder. You should end up with white scans. If you dont, then its the scanner. That said, it does look like a processing problem, sometimes you get it on the end of a roll - have you had more than 24 or 36 shots, maybe it's an "extra".

Aliens!!!!

Yup, it seems to really need the adjacent frame non-empty. Must be light leakage from somewhere. The manual warns about this. So, if the manual warns about this, why has it taken me over a year to figure it out? The answer is the 35mm negative carriers on the Nikon Supercoolscan 8000 are REALLY a pain in the butt. It is difficult enough just juggling the two side-by-side strips of film to line up with the little plastic thingies. It is, I'm convinced, impossible to juggle two film strips, plus two mylar masks, and get everything to line up, (without sort of "helping" things with a finger across the image). And no one, not even the high-priced pro labs I've checked with, will trim 35mm to 6 per strip like the Nikon really wants to see. The optics and digitization with the Nikons are wonderful! The ICE dust removal part of the software works great. For $3000US the mechanics are pathetic. Constant fight with the negative carriers. A little plastic door on the front went "sprong" on my second scan. I see now that Nikon has announced the next generation of this scanner. What did they improve? The optics, the digitization, and the ICE software. The price did drop! From the pictures, the mechanics look identical. Seems to use the same film carriers; at $54, the words "cheap plastic" take on an entirely new meaning.