Higher fog in rotary development of fiber-based paper?

[Marco Annaratone]

I am getting strange results but before searching for the culprit well hidden in my development chain I must ask: is it maybe common knowledge that the development of fiber-based paper in the Jobo increases fog compared to tray development? I am getting differences in the density of 0.1 in base+fog between tray development and rotary/Jobo development. And this higher fog is quite visible. Please assume that there is no obvious reason (light leaks etc), I went through those already myself. Assume same batch of paper, same development temperature, same concentration, same developer from same bottle, same development time. I have six pairs of sheets (six in trays, six with Jobo) and all of them show this, so it is not a fluke, there is something structural going on. Important data point: the tests I have done with resin-coated paper show no appreciable difference between tray and rotary/Jobo development re: base+fog.

Dmax is instead comparable.

Thanks!

[Drew Wiley]

Jobo is a high RPM system, and you're going to get a lot more agitation and oxidation than tray development. Some people develop film in rotary drums, or RC color papers, but not fiber-based paper. Why do you need to do it in a drum? FB paper sizes get soggy and collapses to an extent in a drum, exposing it to intermittent air and uneven development. Not recommended.

[Marco Annaratone]

Why do you need to do it in a drum?
When I print 16x20 my darkroom is too small to use trays large enough for this size. Hence ... the Jobo :(

(And unfortunately I develop 16x20 prints 70% of the time.)

Could slowing down the rotation -- say to 'F' instead of 'P' -- help?

[Drew Wiley]

Jobo just doesn't go slow enough in my opinion. But try the slowest speed. And it might be worthwhile to try displacing any air inside the drum with an inert gas like argon, which is sometimes done to prevent excess oxidation with certain film developers too. You might also try a removable tape on corners and edges of the paper inside the drum, when the drum is still dry.

[Michael R]

Something doesn't sound right about this. You should not be getting development fog on paper even with relatively violent agitation - unless there is something strange about the developer.

For example, John Sexton develops his prints by quickly and continuously yanking the prints out of the tray and slapping them back down (thwap!...thwap!...thwap!...). A Jobo drum rotating at virtually any of its speed settings should not cause paper fog.

Agitation, in and of itself, should not influence fog. Nor should aerial oxidation have any impact on fog under normal circumstances with general purpose print developers.

[Drew Wiley]

Spoken from experience, Michael? I doubt it. There are certain reasons why almost nobody develops FB papers in drums. There was an early Kodak drum system which retained prints using an overlying screen. It was allegedly a finicky system. RC prints don't soak in the solution deeply like FB prints, so retain their shape in a rotating drum. A separate factor is that some drum don't allow for consistent solution flow or drainage behind the print. So chemical residue can get trapped back there, and then potentially come out at the wrong time. That has to be tested for too. We don't know the specific developer or fixer in question either, or if exhaustion of one or the other is involved.

[jp]

I am wondering if things don't get clean in the drum as chemicals change... The FB paper would absorb more and drain slower. Perhaps try a water rinse after developer and stop bath. I have not used drums for prints except for color back in the 1990's and it was too much work then.

Can you build some shelves to stack trays and use trays? It seems trays stacked would not take up any more space than a jobo processor.

[Ben Calwell]

Something doesn't sound right about this. You should not be getting development fog on paper even with relatively violent agitation - unless there is something strange about the developer.

For example, John Sexton develops his prints by quickly and continuously yanking the prints out of the tray and slapping them back down (thwap!...thwap!...thwap!...). A Jobo drum rotating at virtually any of its speed settings should not cause paper fog.

Agitation, in and of itself, should not influence fog. Nor should aerial oxidation have any impact on fog under normal circumstances with general purpose print developers.

I hope John Sexton wears old clothes or an apron when he's splashing about in the darkroom!

[Drew Wiley]

I recommend amidol for those sloshing activities. That way you can prove what you were doing, regardless of how the prints come out. Tie-dyed head to toe, and of course, black fingernails too, just like a heavy metal rocker.

[Graham Patterson]

The fog applies equally to print borders and highlights? Are you doing washing in the tank, or in a washer? This information is not in the original post.

[Michael R]

I hope John Sexton wears old clothes or an apron when he's splashing about in the darkroom!

These days Anne Larsen often does that part. The cool part is that they do two sheets at a time like this. The two sheets are back to back (obviously) and flipped together for the full 2 minutes in Dektol.

[Michael R]

It is possible lack of adequate flow behind the paper might cause problems such as stains, but not overall emulsion fog unless, for example, one is not using an acid stop bath, and is using an alkaline fixer, or perhaps if temperatures are ridiculously high or something.

In any case, with general purpose chemicals, fog should not have anything to do with agitation/aerial oxidation.


Spoken from experience, Michael? I doubt it. There are certain reasons why almost nobody develops FB papers in drums. There was an early Kodak drum system which retained prints using an overlying screen. It was allegedly a finicky system. RC prints don't soak in the solution deeply like FB prints, so retain their shape in a rotating drum. A separate factor is that some drum don't allow for consistent solution flow or drainage behind the print. So chemical residue can get trapped back there, and then potentially come out at the wrong time. That has to be tested for too. We don't know the specific developer or fixer in question either, or if exhaustion of one or the other is involved.

[Drew Wiley]

If the paper is floppy around to a certain extent, due to being softened, what constitutes its front versus the back is somewhat unpredictable. Who knows in this case. It will have to become an experiment in resolving the variables one at a time. 16X20 is a rather big FB print size for successful drum use. What I've thought of hypothetically doing is using thin fiberglass or carbon fiber spring rods in the drum diameter to hold paper in place at both ends. Never got around to that experiment because I didn't need to. Removable moisture and chemical-resistant lacquer-style masking tape could also be hypothetically used.

[Sal Santamaura]

Fog from "flopping around" when developing fiber-based paper in a Jobo drum isn't an issue. That process was well documented. Rather, the challenge is paper being "plastered up against" drum ribs and deforming. Scott Jones worked it all out two decades ago. Here are forum threads in which he walked everyone through the necessary steps:


https://www.largeformatphotography.info/forum/showthread.php?4361-Can-FB-paper-and-JOBO-problems-be-solved



http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=005PED


http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=005Rix


http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=005Wv8


http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=005StJ


https://www.largeformatphotography.info/forum/showthread.php?8370-Jobo

I cannot offer Marco any advice on the fog increase, but don't recall Scott ever reporting that he experienced it.

[Marco Annaratone]

The fog applies equally to print borders and highlights? Are you doing washing in the tank, or in a washer? This information is not in the original post.

The answers so far -- thank you very much to all of you for the help, by the way -- seem to belong to two categories: the former is "if that happens can be caused by this or that", the latter is "it should not happen / there is something wrong". The good observation that Sal has made is that Scott Jones would have noticed it.

I am working on profiling various positive papers and reversed negative papers for in-camera photography, and this increase in fog when I switch from trays to the Jobo happens only with fiber-based papers. That's why I asked if in the standard negative-positive process of developing fiber-based papers with the Jobo (so, no positive paper or reversal development stuff that complicates the story) a notable increase in fog is known to be a problem. From the above I would say that the answer is "no." There may be problems related to the ridges in the drums, I get that, but nobody has ever mentioned an increased fog.

As soon as I have an afternoon free I will contact print a couple of 4x5 Ilford FB sheets with a Stouffer TP4x5, develop one in trays, the other with the Jobo and see what happens when I remove all this positive or negative-reversal development business. And report here what I get.

To answer your question: when I develop the 4x5 FB sheets in trays I do the hypo bath in tray and the wash in tray. When I develop the 4x5 sheets in the Jobo the hypo bath is still done in the drum, the wash in tray. The subject is a Stouffer R2120 step-wedge that I measure with a Heiland TRD2 densitometer.

[neil poulsen]

[QUOTE=Marco Annaratone;1596665 . . . is it maybe common knowledge that the development of fiber-based paper in the Jobo increases fog compared to tray development? . . . [/QUOTE]

Might the same be true of film when developed in a Jobo, versus tray development?

[Marco Annaratone]

Several people in photrio.com developed FB paper in a Jobo, nobody mentions an issue with fog. Except one OP but he says that when he bought new paper the problem did not occur any more. Go figure ...

[Michael R]

Marco, you haven’t mentioned the chemicals/process. It could (possibly) help diagnose the problem.

-Developer
-Stop bath? Acid or water? How long?
-Fixer type? Acid or alkaline?

[Marco Annaratone]

Marco, you haven’t mentioned the chemicals/process. It could (possibly) help diagnose the problem.

-Developer
-Stop bath? Acid or water? How long?
-Fixer type? Acid or alkaline?

I did that on purpose. We are talking about four different papers, three different developers, plus a proprietary reversal process. That's why I restricted my initial question to one specific issue, i.e., whether it is a known fact that using the Jobo increases the fog in a more conventional fiber-based paper development process. I did not want to go into the rabbit hole of splicing and dicing processes that may have nothing to do with the problem. With some papers I use a stop bath, with others I do not. With some I use Ilford MG as developer, with others a proprietary developer. It suffices to say though that the development chain is _identical_ (concentration, times, temperatures, etc etc etc etc) in trays and Jobo. With the resin-coated paper I measure no differences between trays and Jobo, with fiber-based paper my base+fog jumps 0.10-0.14 when I move from trays to the Jobo. Every time, consistently.

Before looking into the specifics of my own processes, I wanted to make sure that the fogging with fiber-based paper was not something that everybody but me :-) knew about it. (I have been using the Jobo for almost ten years, but only with with RC paper.)

[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

[Drew Wiley]

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.

[Marco Annaratone]

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

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.

[Marco Annaratone]

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).

[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.

[Marco Annaratone]

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.

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.

[esearing]

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 .

[MToma]

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.

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!