My new Jobo/Tmax 100 consistency problems solved

[bevdig]

It is no secret that the 2500 reels in a Jobo do not always produce a nice, flat and uniform density across the negative using Tmax developer on Tmax film (and perhaps other film stocks as well). An additional problem is Kodak's recommendation against using Tmax developer with sheet film, and who wants to deal with two different Tmax developers?

Thus began my quest for a cast-iron reliable way to get consistent results from my Jobo. First, I decided to load only four sheets rather than six, which allows for enough space between sheets to prevent fresh developer from "catching" in the narrow spacing you get with six sheets. BTW, I do not have the weird clips you are supposed to fit onto the reels to prevent turbulence and to keep the film from sliding out of the grooves. The next change I made was running a four-minute presoak. Curiously, when I dump this out the water is a bright blue. My thinking is to wet the film surface so that the developer can get started more evenly across the film surface. Then I add Tmax developer diluted 1:8 at 75 degF. The next change I made was to lower the speed of rotation to the "1" or low setting, about 2 rev/second. This gives a "lazy" rotation that keeps the film wet with developer but does not suck liquid into the grooves on the reel, which causes additional agitation on the edges and thus more density. My standard development is 11 1/2 minutes. I also note that I never see the dreaded "dichroic fog" or staining that is supposed to show up when you don't use the RS version of Tmax developer.

I own a densitometer so I can verify the ISO setting for a Zone 1 density of 0.1, and my Zone 8 density is 1.2 or so, which is in line with Kodak numbers for average contrast, for those zone system enthusiasts out there. The Jobo allows for precise repeatability of time, temperature and agitation, and now that I have tamed the film reel issues, my negatives are clean and free of steaks.

I'll wait for comment on the blue water that emerges from a presoak, and why I have no issues with going against Kodak's recommendation on the choice of developer.

[Vaughn]

The blue is just the anti-halation layer coming off...different films, different colors!

Why you have no issues -- might be because you went about it systematically, with thought, and got lucky that everything seems to work! I use the Jobo Expert Drums (4x5 to 8x10) on a motor base, so I am not familiar with the reels for 4x5.

[Michael R]

Thanks for sharing this.

The coloured water would be from anti-halation and/or acutance dyes etc., along with anything else in the emulsion that is designed to come out during processing.

[Sal Santamaura]

...lower the speed of rotation to the "1" or low setting, about 2 rev/second...120 r.p.m.? That's quite fast. What processor do you use to achieve such a high tank rotation rate at the "1" setting? :)

[Peter De Smidt]

According to Kodak, using Tmax developer in a Jobo can lead to dichroic fog. That's why they recommended Tmax RS. If you don't have any fog, well, no worries.

[koraks]

BTW, I do not have the weird clips you are supposed to fit onto the reels to prevent turbulence and to keep the film from sliding out of the grooves.
Well, that already explains part of the problem. The clips/wings are in my experience necessary to get even development / prevent surge marks along the edges, at least with some film/developer combinations. I think the Jobo product identifier for this reel which comes with the black plastic wings is '2509N' - note the 'N' (which probably stands for 'new'). It's a known and well-documented problem...


Curiously, when I dump this out the water is a bright blue. My thinking is to wet the film surface so that the developer can get started more evenly across the film surface.
That's curious. I've only used TMAX 100 (so not TXP320) in sheet film format and the antihalation dye is pink, not blue. I always assumed it was the same color with all contemporary Kodak films...But the fact that you get fancy colors from your first wash is not strange at all. It's the antihalation dye that washes out of the film. Foma films give bright / 'toxic' green for instance.

Concerning presoak: some swear by it, some swear at it. I never presoak. Others do and get good results. If it works for you...

As to the rotation speed: yes, it can make a difference. If you have problems at one speed, try the other.

[NHE]

Does the extra density have any effect when you are printing? You might be able to measure some extra density but it might not matter on the print, of course if we’re talking about a full stop of extra density then that would be an issue.

If you don’t pre-wet/wash the sulfite in the developer usually bleaches the dyes, at least for Kodak and Ilford films. I can’t speak for Tmax 100 but the AH dye for Tmax 400 is a deep blue. The first few washes always come out pink but that’s the sensitizing dyes.

[bevdig]

120 r.p.m.? That's quite fast. What processor do you use to achieve such a high tank rotation rate at the "1" setting? :)

That's a good catch of my math weakness. So yes, 120 r.p.m. is quite fast, too fast. I meant to say 1 rev every two seconds or 30 r.p.m. It's the "1" setting on the Jobo's with the magnet link to the motor, i.e., the older, cheaper unit.

[bevdig]

The replies to my post have been so helpful. They convince me that there is no substitute for learning from direct experience, that is, your own research and testing, and not trusting everything you read or hear. Years ago when I was running my commercial studio, one of my competitors complained to me that his transparencies were always coming out on the dark side of an exposure bracket. So I told him to change the ISO setting on his meter to center the bracketed exposures in the future. He balked at that advice, telling me that "Kodak says it's ISO 100 so how can I change the meter ISO if that's what Kodak says on the box?" It's the old story of not believing your own eyes and reminds me of a George Orwell quote: "To see what is in front of your nose is a constant struggle."

[bevdig]

My roll film regime with the Jobo has been the same for years and never a problem with no presoak and the 5 1/2 minute, 75 degF time, and I never see any colored water, perhaps because of not presoaking. Edge density build up was not so much a problem with the 2500 reels as was the tendency for 1:4 dilutions of Tmax developer to get "stuck" in the small space between sheet film when loading six sheets, leading to splotchy development. But as you said, the wings on the newer reels may be necessary for sheet film for just that reason.