What is causing these smudges?
I'm pretty sure this is a processing problem - it's happened on negatives from two different medium format cameras. My developing is:
Kodak T-Max Developer, 6:45 at 20 degrees celsius - time adjusted according to Ilford compensation chart
Ilford Rapid Fixer - for 3-5 minutes, depending on how fresh the fixer is
FotoSpeed RA50 wetting agent
Paterson Universal tank, Samigon Multi-Format reel, agitation by inverting 5 times every 30 seconds.
These marks appear on both T-Max 400 and Acros 100. Any idea?
It matters to determine which way the film runs through the camera.
If that is on the edge of the film and not width wise, I'd GUESS you didn't have enough developer in the tanks and the top edge is underdeveloped.
That was on a Rolleicord Vb, although the same also occurs on a Rolleiflex 3.5F. Looking at the negatives, it seems to occur mostly on the photos towards the end of a roll, typically negative 8 onwards.
It's on the edge indeed. Is 500mL inadequate for a Universal tank?
That's uneven development and air bubble as Bruce says. Could be not enough developer in the tank, or the reel has moved up the column during agitation. Ive seen reels move in Paterson tanks they usually have a collar that helps prevent this. 500ml is fine as long as the spiral isn;t loose.
500 ml = 16.9070114 US fluid ounces
IDK that is close to what I use and the patterson takes a tad less than some no name tanks I have.
If it's the same patterson I've used (System 4 possibly, I forget what mine is called) I never go less than about 18 oz for a 120. A 120 roll doesn't extent as high in the tank as 2/135 rolls but I still don't skimp.
I think the bottom of the tank will list needed capacities.
edit: per usual Ian makes an excellent point. I actually have one of those plastic collar and some of the reels are looser than others.
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That might just be the ticket actually - now that I think about it, I've opened the tank before and the reel wasn't completely at the bottom of the tank. The inversion agitation and and weight of the liquid must contribute to it moving.
Both my Super System 4 tanks didn't come with any form of collar though, and I can't put an empty 35mm on top because there isn't enough space. Is there any well known improvisation for it? I was thinking rubber bands but I'm sure there must be a better way...
I've heard of rubber bands I think but just add an extra ounce and be done with it.
I don't like foreign matter in a tank, the tape on a 120 roll even bugs me
Another thing to consider, I always tap my tank bottom on a hard surface after inversion/agitation sequence. This dislodges any air bubbles and keeps the reel on the bottom of the tank if it's loose.
I usually run 2 120 rolls on one reel so I want as much developer in the tank as possible and always fill it but overfilling can cause issues also.
Paterson System 4 and Super System 4 need 500ml per 120 film, I've been using them since their introduction rather a long time ago
Ian, like I said I run 2 rolls in one of those.
I've read the contentious arguments about how much D76 is actually needed per surface area and I like it 1:1.
Am I asking for trouble doing this if I'm careful to completely fill the tank @ 1:1 with 2/120's or 1/220?
Have you done this?