Higher fog in rotary development of fiber-based paper?

Sal - same cause. Fiber-based papers get soggy and do not maintain consistent diametrical shape atop ribs like RC and poly-based print media do. Corners can go floppy too. I tested for this by using a cap with a big enough center cutout to peer through while it was happening. Ribs are necessary for proper stop and rinse flow behind the print. But given enough solution volume (sometimes too much to be economical), even the elevation difference between the walls and the ribs would not be an issue if things are properly slowed down enough to prevent wild sloshing. Yeah - I'd like to efficiently solve the same problem, not in reference to Jobo, but in relation to my own 30X40 inch capacity drum system, which is capable of far lower RPM than a Jobo. Works great for big color prints. Doing anything fiber-based that size in a drum is going to take some extra ingenuity, however. I have no doubt I could come up with some kind of efficient practical answer within the bounds of my own shop capabilities. But I'm in no hurry. Already have plenty of other projects on my plate.

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Originally Posted by Doremus Scudder

No one has mentioned developer oxidation and subsequent emulsion staining yet. I've had some issues with this with a couple of different developers (especially when the developer has had a few prints run through it).

Since you don't want to divulge which developers you are using, I can't speak directly to them. However, if oxidation and staining is the problem, anything that helps reduce developer oxidation should help. That means slower agitation (or even rolling the drum by hand), maybe adding a bit more sulfite to the developer and using the freshest developer you can.

If you can eliminate the fog/staining by slowing agitation and using fresh developer, then this is almost certainly your problem.

Best,

Doremus

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Thank you for your input, I will slow agitation down and see what happens because I only use fresh developer. It's not that I do not want to divulge which developer I am using, is that I do not know what's inside it. It's not mine. But anyway, I have the same identical problem -- with another FB paper, not the same -- with 1+9 Ilford Multigrade. And again, all this does not happen with RC paper. Is oxidation a known problem with FB paper but not with RC paper?

As I said, I realize that my situation is not standard and it very well be that my problems are of my own doing :-) but before drilling into them I wanted to make sure that fiber-based paper does not get _intrinsically_ fogged when developed in the Jobo.

Thanks again.

I just want to remind those helping me here that my fogging problems happen with tiny 4x5 sheets (both RC and FB) developed in a small 2820 Jobo drum (or in 5x7 trays).

Do you load the drums in the same location as you would tray develop? I just want to rule out different safelight time conditions between post-exposure and developer immersion.

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Originally Posted by Graham Patterson

Do you load the drums in the same location as you would tray develop? I just want to rule out different safelight time conditions between post-exposure and developer immersion.

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Same location. In fact, when I develop in trays I do it in almost total darkness because the two positive papers are sensitive to some red light and I had to change two "safelights" because they were not safe at all. Loading the drums is done in total darkness. Loading the chassis is done in total darkness for all four papers.

Thought - just because you use a drum doesn't mean you have to use rotary agitation. just fill the tube with developer and agitate slowly - or use dump refill method .

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Originally Posted by Marco Annaratone

Same location. In fact, when I develop in trays I do it in almost total darkness because the two positive papers are sensitive to some red light and I had to change two "safelights" because they were not safe at all. Loading the drums is done in total darkness. Loading the chassis is done in total darkness for all four papers.

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Hello Marco! Did you manage to trace this issue down? I'm embarking on my own rotary-processing of prints, and would like to leech off of your experience. :) Thanks!