Over-Agitation with Paterson Tank and Uniroller

[pwadoc]

I recently picked up a Uniroller off Ebay to make my C-41 process a bit easier, and I've been noticing that my rolls of 35mm have been showing signs of what I believe is over-agitation—specifically I'm seeing what look like shadows or streaks originating from the socket holes in the film. I'm using:

Kodak Flexicolor Lorr chemistry
Paterson 2 reel tank
Uniroller for agitation

I'm using 500ml of developer (one-shot) rather than the 600ml I generally use for hand agitation, because I've read that I don't need as much developer for continuous agitation, but I'm wondering if that might be part of the problem? I'm developing for 3:15 at 100F as the documentation recommends. I've been re-using my bleach and fix for longer than recommended, but my sense is that weak bleach or fix wouldn't cause this specific problem.

I've attached a representative frame—this one was the most noticeable, it tends to be very subtle on other frames to the point where I don't really notice it until I start playing with the contrast in Capture One. Apologies for the dust/color accuracy, this was just a quick scan to demonstrate the problem. Any guidance or recommendations would be greatly appreciated!

 

[koraks]

My first thought is that your tank may not be perfectly level and the volume of chemistry may be a bit low. To rule out problems with the bleach or fix, try re-bleaching and fixing for an extended amount of time or (preferably) with fresh chemistry.
Scans can be misleading, but this image looks like it might be underdeveloped.

 

[pwadoc]

My first thought is that your tank may not be perfectly level and the volume of chemistry may be a bit low. To rule out problems with the bleach or fix, try re-bleaching and fixing for an extended amount of time or (preferably) with fresh chemistry.
Scans can be misleading, but this image looks like it might be underdeveloped.

Hrm, now that you mention it, the Paterson tank sits on the Uniroller at an angle. I'm wondering if that's the source of my problems.

 

[koraks]

Make sure it's decently level, otherwise uneven development is a real risk. I'd fix this first and then see if you have any additional issues to resolve.

Looking once more at the amount of chemistry you use, it may actually be too much. FYI, I use a Jobo 1500 series tank, a 1510 for 35mm, and it requires only 150ml for rotation agitation, while it takes 250ml (IIRC) for hand/inversion development. As I recall, a Paterson 2-reel tank takes 500ml for hand/inversion development, so logically, for rotation (at a level base) it would require something along the lines of 300ml.

 

[MattKing]

If you cannot level the tank, increase the amount of fluid in the tank and at least once per minute manually reorient the tank on the agitator by 180 degrees.

 

[thuggins]

I hadn't seen one of those devices. It looks like it would be rather dangerous in a water bath.

I built something similar that does work in a water bath. It fits a one pint stainless steel tank and rotates it about 10 rpm. I fill it full, just like for inversions. The time is the same as for hand inversions - 6:15 for the first two rolls, increase 15 seconds for each subsequent rolls (e6). The film always comes out right.

It is hard to picture how the sprocket holes would interact with the development; they are largely covered by the reel. Have you tried any 120 to see if there is any nonuniformity there?