>>3124619Dude, first up, stand dev is a total meme and you should give it up. Rodinal is already cheap as dirt at normal dilutions, there's no need to push it further and risk fucking your films just to save you standing at the sink for 20 minutes.
Secondly, if you did it all in the one batch, I think it's quite unlikely you'd have a strong gradient on one edge of BOTH films. If it was a case of your solution settling and concentrating activity at the bottom of the frame, you'd also expect to see a substantial density difference between the two rolls.
What is instead very likely is that your scanning rig is giving uneven illumination.
I wouldn't bother rescanning these though.
Simply duplicate your layer, set the top one to multiply, then use a gradient mask to flatten it out.
