Non-uniformity when loading 2 rolls of 120 per reel (B&W reversal, Jobo 1500-series tank)

[iandvaag]

I’m still (after 3+ years!) trying to figure out a workable B&W reversal process. I’m using some Kodak formulae (listed below). The film is Ilford Delta 100. I developed a step wedge alongside the film that I haven't yet measured on my densitometer, but this process has historically given me very good results, ( >3.5 Dmax, good contrast), apart from the non-uniformity.

All solutions were prepared fresh today, except the dichromate bleach. Agitation was done manually for the first 30 seconds, then using a Jobo CPE-2 on motor setting “2” (the faster, recommended one.) I use the 1500 series tanks. Process temperature was 20 C. Note that I develop B&W negative, C-41 and E-6 all using the same Jobo tanks and processor, and I have not previously noticed non-uniformity issues this severe in any other process. I have previously noticed this issue in my reversal process. Previously, I had non-uniformity throughout the roll, but now it seems like it's only in one spot.

I load two rolls of 120 film on one reel, using the red tab film separator to prevent overlap. As I write this post, I notice that the problem occurs on the penultimate frame (frame 11 of 12, since I’m shooting 6x6) of the innermost roll of 120. Any ideas on how to solve this? I guess the obvious answer is to just load one roll, but that means developing takes twice as long and uses twice the volume of chemicals.

Here is a photo of the innermost ends of the film when loaded on the reel. Note that these are stereo images, which is why there are two “duplicate” frames. Note the line of non-uniformity marked by the red arrows, which appears as an area of lower density (i.e. more first development).

Process
Pre-rinse...................................................2 min
First Developer Kodak D-67...................15 min
Stop (2% acetic acid)...............................30 s
Rinse
Bleach Kodak R-9 (dichromate).............5 min
Rinse
Clear Kodak CB-3 (1% NaSO3)...............1 min
Rinse
Light exposure
Second developer Dektol.......................4min
Stop (2% acetic acid)...............................30 s
Rinse
Fix Photographer’s Formulary TF-4.......3 min
Wash.........................................................10 min

Many thanks for your consideration.

 

[koraks]

How much chemistry do you use?

Is there a chance that your light exposure somehow fails to penetrate to the innermost loop of film (as this seems to correlate fairly well with the examples you posted)?

FYI: regardless of what is recommended, I noticed that I had more problems with uneven development with Jobo tanks on a CPE2 at the high-speed setting than at the low-speed rotation setting. However, this was related to longitudinal unevenness (ie along the length of the film), so I don't think this would necessarily be a solution for you. I've read conflicting reports on which speed setting to use, with some people asserting the high-speed setting is the right one and others asserting that 'wagon track' unevenness results when using the high-speed setting, particularly with color reversal processing IIRC.

 

[iandvaag]

Interesting. I'd never heard that some people find the lower speed setting to give better results.

Today I was using the 1510 + 1530, which recommends 470 mL of processing solution. I use 500 mL to be safe. Usually I do 6 rolls/3 reels using the 1520 +1530 which recommends 570 mL of solution, and I use 600 mL, which is the limit of the CPE-2, and which I don't believe is over-filled.

It might be possible that the light doesn't penetrate that part of the reel. When I run another batch tomorrow, I'll take it off the reel and check for non-uniformity. Then I'll know if the problem occurs prior to 2nd exposure or not.

Thanks for the advice!

 

[iandvaag]

Well, I did some more tests and more developing today.

I first tried mixing up some permanganate bleach and otherwise running the same process as yesterday. The results were about the same. Here's the same problem I described in the OP, this time bleached with permanganate:

Next I tried "dip and dunk" rather than rotary processing. The first two steps (first developer and stop bath) are the most critical. In the dark I filled the tank with the correct volume of developer for inversion. I then immersed the reels on the spindle into the tank and snapped on the lid. I agitated continuously using slow inversions so that the development time would be comparable to rotary agitation. At the end of development (in the dark), I removed the lid, pulled out the reels on the spindle and immersed them in a second tank full of stop bath. the rest of the process was carried out using normal rotary agitation for convenience, as all other steps are "to completion". I hoped using this method could inform me as to whether there is a problem with my technique/speed at pouring in the solutions by eliminating that variable.

I also removed the film from the reels to fully inspect it at the re-exposure stage. At this point, I still saw non-uniformity on the 11th frame, but only for one of the two reels and it looked different. The other non-uniformity defects which I had previously seen randomly distributed along the length of the roll were not present. This time non-uniformity at frame 11 for the one roll looks more like a light-leak, as if the backing paper had not been sealed nicely against the flange of the film spool. Maybe this is just a coincidental light leak at the same place on the roll. I will be doing more development tomorrow.

If I were to make a guess, I would say that perhaps the reason why this batch was an improvement in uniformity is because I was using a different agitation regime, but I don't really have any good reason as to why I think this is the reason.

I'm really not sure what else I can try to resolve this issue. I reread the chapter in Haist v2 on reversal processing twice today, as well as any APUG thread I could find about reversal processing uniformity and also about loading 2 rolls of 120 onto Jobo 1501 reels. Haist mentions that image non-uniformity can result from insufficient wash between FD and bleach, but I'm reasonably confident that is not the case (I'm using a stop bath and 10 changes of water over 4 minutes with lots of agitation.) The Kodak reversal processing guide indicates that the clearing bath might be the culprit, but I don't see any permanganate or dichromate stain after using the clearing bath. The image density is visibly reduced when I inspected the film during re-exposure, so it's not the re-exposure itself that is a problem. It's as if the inner part of the reel is causing increased action of the first developer in this spot.

Any advice is appreciated! I'm feeling a bit defeated as an experimentalist as to what I can try to do understand this problem better.

 

[KPA40]

For me, it looks like the end of the film in the reel is in contact with the surface of the underlying winding. The development could therefore be uneven at this point. A film is most curly at the center of the film spool. I suspect you are winding the film with the end (frame 12) first into the reel. Try to thread the film into the reel in reverse (frame 1 to the center of the reel ). Or simply thread the film with the emulsion outside into the reel.
I hope that will help.

Regards Olaf

 

[Trey]

Have you tried using metal or Patterson tanks?

 

[Pentode]

Have you tried using the suggested quantity of developer instead of increasing the amount as you have?

It seems to me that if you use more than the recommended quantity the outer part of the roll would be going in and out of the chemistry during rotary agitation but the center part would be submerged for the entire time.

That’s only theoretical, but it might be worth a try.

 

[grahamp]

This is the inner film of two stacked on a reel only? My guess (and it is only a guess, as I have not seen this when I do 120 stacked), is that the end of the film is not fully past the red separator when it is pushed in. That distorts the film a bit, and probably affects the agitation effect.

 

[Adrian Bacon]

For me, it looks like the end of the film in the reel is in contact with the surface of the underlying winding. The development could therefore be uneven at this point. A film is most curly at the center of the film spool. I suspect you are winding the film with the end (frame 12) first into the reel. Try to thread the film into the reel in reverse (frame 1 to the center of the reel ). Or simply thread the film with the emulsion outside into the reel.
I hope that will help.

Regards Olaf

I occasionally have that issue too. Sometimes the direction you feed the reels makes a difference.

 

[Adrian Bacon]

Have you tried using the suggested quantity of developer instead of increasing the amount as you have?

It seems to me that if you use more than the recommended quantity the outer part of the roll would be going in and out of the chemistry during rotary agitation but the center part would be submerged for the entire time.

That’s only theoretical, but it might be worth a try.

The suggested quantity is the minimum you have to have to cover the film. I always do more and rarely have issues, though depending on the film and how curly it is sometimes have issues if I load the wrong end of the film first.

 

[mshchem]

This is the inner film of two stacked on a reel only? My guess (and it is only a guess, as I have not seen this when I do 120 stacked), is that the end of the film is not fully past the red separator when it is pushed in. That distorts the film a bit, and probably affects the agitation effect.

This sounds reasonable. I use IR night vision goggles. I've had to visually inspect to make sure the first roll,of 120 was on far enough to be able to see the red tab between the two films. I found that it's not always fully wound and the red tab pinches the film.
At one point I was so frustrated with Jobo reels that I got the Hewes 120 for Jobo. Very uniform development. I've never had this problem with B&W, E-6 or C-41. Never tried monochrome reversal.
I'm back to using Jobo reels but they still, pain me

 

[iandvaag]

Thanks for all the comments!

is that the end of the film is not fully past the red separator when it is pushed in. That distorts the film a bit, and probably affects the agitation effect.

Very good suggestion, and I have made this mistake in the past, but I'm reasonably confident that's not the problem this time. It's pretty clear that you've done something wrong if you try to push the red tab in without fully loading the reel on. The tab will not go in easily, and you will crease the film base if you force it.

Have you tried using the suggested quantity of developer instead of increasing the amount as you have?

Good thinking. I generally follow manufacturers recommendations to the letter, but I had tried slight "overfilling" in the past with B&W negative, E-6, and C-41 processing and never had any problems. The reason I did so was because I had read some users' experience that they had underfilled the tank using Jobo's recommended volume, but I think this was likely user error in measuring, or properly leveling the Jobo. I've not ever seen any difference in using the recommended volumes, or by overfilling slightly by less than 10%. I see no reason not to follow Jobo's recommendation precisely. Thanks for the suggestion.

Have you tried using metal or Patterson tanks?

Yes, I did try this at your suggestion, and the result was very good, no problems related to processing that I could notice at all. Thanks.

I suspect you are winding the film with the end (frame 12) first into the reel. Try to thread the film into the reel in reverse (frame 1 to the center of the reel ). Or simply thread the film with the emulsion outside into the reel.

Unfortunately I ran out of film and time to try this, but this is a great suggestion. I suspect if I were to load the reel in reverse with frame 1 to the centre, that the defect would appear on frame 2, but I can't say for sure not having run the test. As for loading the film emulsion side out, I intend to try next time I develop.

My conclusion:
It seems like the problem is the agitation on the CPE-2. I developed three batches with manual agitation, twice with Jobo tank and reels, and once with Paterson tank and reels. Someday I'd like to get a larger Jobo with 2500 series tanks, perhaps this would not be an issue. I seem to recall reading some literature from Jobo that the 2500 series tanks are the ultimate in consistency, more so than the 1500 series. For now I will stick to manual agitation.

Many thanks to all who replied. I really appreciate it!

 

[koraks]

Re the 2500 VS 1500 tanks, I can only say that I've seen irregular development with both them, in different formats. The geometry of the reels seems to be an important factor.