Chronic uneven development in sheet film with Jobo

steveo_mcg

steveo_mcg

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First up, I can't currently demonstrate this due to POTY rules but I've got too much of a back log to not do any developing over the next few weeks.

I've been developing my sheet film in Jobo tank with a 2509n reel for 5x4 sheets and 80% of the time. I switched from Rodinal to Obsidian Aqua (a pyro developer) which I'm liking and helps contain highlights in my city night shots but OA doesn't like rotary developing so I've been using using the big jobo as an inversion tank (This isn't a problem with OA as its fairly cheap.)

In the last batch of 4 sheets, one had big streaks down it, one had mottling in the sky and two were perfectly fine what I failed to observe is if the two poorly developed ones came from a similar position in the reel. luckily I've got another (undeveloped) shot of the ruined one so I'd like try and work this out before putting more exposed film through.

I've got some ood fomapan I can waste on this so I'm thinking take a few pictures of the kitchen wall to have something to develop.

Any suggestions of what could be causing this so I can try to replicate it with the test shots.
 
are all the chemicals well mixed before going in the tank?
 
Should be, but I'll make sure and given them a good stir before pouring them in.
 
I haven’t developed film since the 70s. It was possible then to get a pre- developer stuff. This just made the film wet and was then tipped away. Its purpose was to allow the developer to come into contact with all of the film at the same time. Could this be your problem?

Perhaps it was surface tension that prevented the entire surface becoming wet at the same time. It wasn’t really necessary to do this with 35mm, just tap the developing tank on the table 3 times.

I hope this is all your problem is.
 
Steve, sounds like you are doing two different things from before: (a) you've changed from Rodinal to Obsiquian something, and (b) you're not using rotary but inversion for the Jobo. Is it possible to go back and change only one of these?
 
I haven't got a jobo but have recently started using pyrocat-hd. The instructions say that it is essential when using a jobo to presoak the film to prevent uneven development. Might be worth trying if you don't already do this.
 
Meyssonnier said:
I haven’t developed film since the 70s. It was possible then to get a pre- developer stuff. This just made the film wet and was then tipped away. Its purpose was to allow the developer to come into contact with all of the film at the same time. Could this be your problem?

Perhaps it was surface tension that prevented the entire surface becoming wet at the same time. It wasn’t really necessary to do this with 35mm, just tap the developing tank on the table 3 times.

I hope this is all your problem is.
Click to expand...

wickerman said:
I haven't got a jobo but have recently started using pyrocat-hd. The instructions say that it is essential when using a jobo to presoak the film to prevent uneven development. Might be worth trying if you don't already do this.
Click to expand...

I think you guys might be right, I'll give it a presoak next time and see if that helps.

ChrisR said:
Steve, sounds like you are doing two different things from before: (a) you've changed from Rodinal to Obsiquian something, and (b) you're not using rotary but inversion for the Jobo. Is it possible to go back and change only one of these?
Click to expand...

Nah, unfortunately not. My rodinal is gone and the OA oxidises very quickly in a rotary processor so you effectively lose film speed which I can't afford I'm already at longish exposures. TBH I was never happy with rotary processing rodinal anyway it seemed to lose something, I got better tonal qualities from 120 fp4 than I did from 54.
 
Bah, two more lots of four done. One in each batch has some streaking both were in different positions on the reel. Very frustrating. I've got no problems with 120. I wonder if it's the film holders causing light leaking rather than development....
 
steveo_mcg said:
Bah, two more lots of four done. One in each batch has some streaking both were in different positions on the reel. Very frustrating. I've got no problems with 120. I wonder if it's the film holders causing light leaking rather than development....
Click to expand...
Post some up.
 
First and most obvious.
Development problems? by Steven, on Flickr

Secondly it's less obvious but in the highlights in the top right there is distinct mottling.
Development problems? by Steven, on Flickr

The ones from the latest batch will have to wait as they're yet to be scanned but it's similar to the first on the light box.
 
Just realised I never followed this thread up.

As far as I can tell the issue was caused by inversion processing the sheets with the 2509n. I think if you put more than one sheet in each side they move and touch each other causing the streaking and mottling. So you can either do 1 or 2 at a time or switch to rotation.

I've now done dozens of sheets by rotation (in a different developer) and they've all been fine.
 
Always good to get a successful update. Glad it's sorted.
 
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