Jobo 4x5 processing problems

[neal_shields]

I am just starting to process 4x5 in a Jobo CPE 2 plus with a 2551

tank. I process 12 at a time with 560 ml of chemicals. (The tank

says 8 but the reels hold 12) Most of the time things work fine.

 

Three batches ago, I had two negatives ruined. They were pink

overall, and had areas near the one end where they were completely

clear. There were other small areas with normal image but most of

the negative was a very dense pink with no visiable image. They were

next to each other on the bottom reel of the drum. I decided that

the negatives had been damaged in the car by heat, and took

precautions to keep my plates cooler.

 

Last night, it happened again. Three on the same side of the reel,

bottom reel, everything else in the batch looked fine.

 

This has happened with both Tmax and Delta 100 and with both Tmax and

Ilford developer.

 

Processing temperatures are on the high side because our tap water is

usually 75 to 80 degrees here in the summer.

 

The tank is very close to level, and the motor base turns about 3

turns before reversing and slowly rotates the reel (doesn't stop and

reverse at the same place every time) during processing. I processed

for 9 minutes.

 

I am stumped.

 

Neal

[neal_shields]

My wife's theory is that residue from the Hypo dried onto the wall of the tank, (I dry it laying down) and that it attacks the film during the pre-wet. I pre wet for 5 minutes. I wouldn't think there could be enough dried hypo left for that? I usually wash in the tank for about 5 minutes with running water and dump the tank several times.

 

Neal

[carl_weese]

It sounds as though the sheets were stuck together during processing. The no-image is because developer couldn't reach the film, and the deep pink is uncleared emulsion and anti-halation backing. I don't know how that tank/reel system works but I'd suspect your problem has to do with running 12 sheets instead of the recommended 8.---Carl

[jim_kish]

Neal,

 

It does sound like the developer isn't getting to the film, two things I would look at...

 

First, are you sure that 560ml is enough volume? I use the tank 1/2 the size of yours (6 sheets) and use 600ml of solution. Whenever I used Jobo's recommended puny amount of developer I never got even development. Additionally, if you use a dilute developer, you may need more of it (I use PMK, which needs 100ml/sheet).

 

Second, do you use the "wings" that snap into the side of the reels? In my experience, they do keep the film from sticking together.

 

Last, I don't think residual hypo is the culprit.

[bob_moulton7]

I have used that system for several years. I would suggest two possible problems: The pink images suggest depleted fixer. and/or the failure of the fixer to remove the dye Kodak incorporates into Tmax films. I don't use Ilford film, so I cannot comment on the specific problems.

The amount of solution you are using seems small. I know Jobo says you can use 560ml, but Jobo also would add that should be straight not diluted developer.

For what it is worth, I use 900ml of solution for 12 sheets of TMax 100 all the time successfully. I use TmaxRS, since Kodak stipulates that Tmax developer is inappropriate for sheet films. I add the B to the A solution, and call that stock, and then mix it 90ML TmaxRS + 810 ML water. I prewet 5 minutes and process Normal at 10 minutes.

I would check the freshness of the fixer and maybe try a new bottle of TmaxRS. Unless you have some critters in your water supply I can't see what else could be going wrong.

Hope this helps.

Bob

[neal_shields]

I do use the wings, and the fixer is a new bottle. I think I may be pushing the limit on using so little developer and fixer. I will try using more, and see if that helps.

 

Thanks

 

Neal

[neal_shields]

I took your advice for this night's batch and used 1000ml for 10 sheets, and everything came out fine.

 

Thanks Neal

[john_hicks___]

For some reason the solutions didn't contact the film sufficiently; look at either insufficient solution in the tank and/or two sheets slipping together and touching.

[wilbur_wong]

I have 2 or 3 times have had negatives stick together in a 2551 tank. (I process C41 color negatives generally) I feel that most times that this has happened, I have been sloppy in inserting the negs into the reels (I use jobo's loader, and I assume you do as well), once it happened because I left out one of the "wings" that help insure the negatives don't slide out of the channels during reversing motions.

 

Basically, after I have all the spaces filled on a 4 x 5 reel, I feel the exposed negative edges simultaneously with my fingers on the reel before inserting the wings - I'm generally pretty confident that each negative is properly placed after this procedure.

 

I continue to process 12 sheets in this tank, but I do always process with at least a minimum of 600 ml of chemicals, not 560.