>>2862710 >>2862710 >>2862682 Circled in green is a water mark. Use a wetting agent in your final rinse.
Circled in red is uneven development, or possibly even another watermark, stemming from not immersing the whole negative quickly when you're developing. (Or possibly printing, is this mark definitely on the neg?)
The solution is to use enough developer to entirely cover your negs, you tight bastard. Or fill the tank quickly.
It happens because if there is just a splash on a part of the neg before the whole thing gets wet, it will get a second or so headstart on the rest of the development.
It's more common to see this effect on prints though, as the paper dev time is a lot shorter, so small time differences like that are exacerbated, and it's easy when putting a print in to develop to accidently leave a corner hanging out for a second or two.
