Occasional overlap damage when processing 5x7 in Jobo 3006 drum

[badbluesman]

When this damage occurs, the film seems to have twisted around in the cylinder and overlapped itself. The result is an undeveloped or under-developed area in one corner (see attachment). The intensity of the blemish varies depending on how early in the process the overlap occurred. The attachment shows a severe case. Sometimes it is less pronounced.

I recently looked through more than 2000 5x7 proofs and could only find three examples of this problem. But I have a memory of throwing out quite a few sheets that had been damaged in this way. It seemed to be occurring about 10% of the time.

I never had this problem when processing 4x5 in the same drums.

I am loading the drum exactly as shown in the Jobo manual (I have two 3006 drums so that I can process continuously).

I am using 600 ml of chemistry for six 5x7 sheets (the manual calls for a minimum of 510 ml).

I have the speed set at 4.

I am processing at 24 degrees Celsius (it is hot where I live and often impossible to get the water any cooler):
Old T-Max 400 at 6 minutes in Xtol 1:1, New T-Max 400 and FP-4 Plus at 5.5 minutes.

Has anyone else ever had this problem? Can you see anything in my processing method that could be causing it?

I have heard that switching to the 3005 drums (designed for five 8x10 sheets) would solve the problem. Any ideas or observations are welcomed.

https://joelpickford.com

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[Sal Santamaura]

...Has anyone else ever had this problem?...

Yes, I have.

...Can you see anything in my processing method that could be causing it?...

No.

...I have heard that switching to the 3005 drums (designed for five 8x10 sheets) would solve the problem...

That's what I did and it solved the problem. I use the 3005 for 5x7 and whole plate, reserving my 3006 drums for 4x5 only.

I had the same problem with 8x10 in the 3005. Now I process 8x10 only in the 3004. Larger diameter chambers resolves the issue.

Edit: I failed to address this:

...I have the speed set at 4...

That doesn't specify what the actual rotation speed of your processor is. See this post:

https://www.largeformatphotography.i...l=1#post836600

If you're actually rotating the drum at 86 r.p.m., rather than the optimum approximately 45 r.p.m., it will exacerbate the problem.

[tgtaylor]

The problem is that you are pushing down the film unevenly when loading - the sheet kind of corkscrews resulting in the overlap. I had the same thing happen once when using the 3005. The solution is to not to push the film all the way in. Leave a little protruding and check that both corners are even with each other before fully inserting pushing the film with both hands on the corners. To be sure you can lift the sheet slightly with both hands and push down. That ensures that the sheet is not overlapped.

Thomas

[Bernice Loui]

Been using Jobo 3006 since the 1990's, currently have three of them. Never had a problem with overlapping film during development. This is likely caused by not seating the sheet of film on to the bottom of the film cylinder. If there is a gap between the bottom of the cylinder and sheet of film the film can rotate and spiral during processing. If the sheet of film sits at the bottom of the cylinder, the sheet of film will have difficulty trying to rotate during processing.

Leave a small area of the sheet film above the cylinder during the loading process. This will help keep track of which cylinders are loaded and which cylinder is not. Once all the cylinders are loaded, then gently press the sheet of film on to the bottom of the cylinder. Once all sheets of film is properly seated, out the top on then proceed to process the film.


Bernice

[Sal Santamaura]

...Once all the cylinders are loaded, then gently press the sheet of film on to the bottom of the cylinder...

That is not correct for 4x5 film:

https://img1.wsimg.com/blobby/go/059...=1626884388196

[Vaughn]

No issues so far...I have noticed some slight 'corkscrewing' with 8x10, but nothing that affects development. It might help that I reverse the direction of the rotation of the Expert Drums (3006 w/5x7, 3005 with 5x7 and/or 8x10) every minute or so. And using a motor base, the rotation speed is far less.

[badbluesman]

Here is a general reply to the entire thread that I hope will address everything:

1. Yes! The 3006 drum instructions DO say that 5x7 film should be pushed to the bottom of the cylinder, while 4x5 should be pushed down to just below the top of the cylinder. Thanks for this important tip!

2. Regarding my speed setting of 4: I'm not sure if I have a newer or older Jobo unit. I think I bought it brand new around 1998 or 1999. If it is the newer one, then at a setting of 4, I am spinning twice as fast as I should be. This might explain my short development times: 6 minutes in Xtol diluted 1:1. I am also presoaking for 5 minutes on speed 4 before pouring in the developer. Perhaps the film is getting twisted in the pre-soak

3. I will try pushing the 5x7 sheets all the way to the bottom off the cylinder. I will also try to determine if I have the newer or older motor. If it is the older one, then my speed is about right at 4. If it is the newer motor, then I will try to reduce the speed by half and test for new development times.

4. Any suggested development times for new TMAX 400 at 45 rpm in either Xtol or D-76 (straight or 1:1)?

[Jim Noel]

Mine has a rewound early motor and works well. I ALWAYS develop film at the slowest possible speed to get the drum rotating.

[badbluesman]

According to my Jobo Manual, which has a publication date of 07/1997, the speed setting of 4 runs at 50 rpm. I will try slowing it down a bit and lengthening my developing time. Six minutes is a little shorter than I would prefer for a normal developing time (for the sake of evenness).

[Duolab123]

I have a new CPP3 the recommended speed for Expert drums seems fast to me. I have a mid 90's CPP2 as well, I realize now I was running slower than what Jobo recommended. Those big drums put a lot of stress on things.