Jobo 4x5 reels and blotching

I found posts here identifying a blotching problem and I was able to use that information to determine that my process was suffering the same issue, that is I have blotching in the middle (most often) and occasionally on the edges when I do 6 sheets per reel. Backing off to 4 sheets (back and front no middle sheet) fixes the problem.

Is there a way to fix this? I have used the same process for about 4 or 5 years and this only recently showed up, as in the last 8 or 10 months. I have the 2500 series drum and 2 4x5 reels. I was wondering if it was some sort of chemical build up on the reel that I could clean? or is the acetate base on the film different? I am using Provia and Velvia (50 & 100).

Any suggested solutions to getting back to 6 sheets per reel?

Thanks in advance.

Todd, what kind of reels are you using? 2509 or 2509N? The N makes a big difference.
2509 reels had a design problem that was solved by the newer 2509N.
I can develop six sheets at once with my 2509N reel. No problem. I did it several times. All you have to do is use the black stoppers and change the rolling direction every few turns. Whenever I got uneven development it was either because I was too lazy to use the stoppers, or because I rolled the tank in only one direction.

These 2509 reels. I to have been irritated with weird density issues using them. So now, like you I dev 8 sheets, not 12, and do away with the black plastic wings. Very even negs, tons better than 12 sheets with the wings. I an now resigned to the reels only working well with the 4 sheets.

At what speed do you run your drum? Jobo suggests using a faster speed.

Thanks for the feedback. I will have to check the N v. not N. I did not know there was a difference.

I actually always used the wings. When I dropped to 4 I also used the wings and it did fine. I may try them without on 4 then for a test.

I use a CPE processor so by definition I am lazy :D but it always changes direction.

I just found it unusual that this issue just started up after 4+ years...Truthfully I have never had this problem until recently.

My processor only has off and one other speed, I don't have the 2 speed.

I purchased a new drum and new reels (because if I am stuck doing 4 I will need to develop more often) so I am curious to see if these new ones will do 6 sheets again.

FWIW: I have not had any problems. I use 2500 series drums, the earliest reels without any clips or wings or whatnot on a Unicolor reversing base that runs about 30 rpm and reverses every 1 1/4 turns of the drum. I swap the drum end-for-end a few times during development. Developers are TMax RS, D-76 and HC-110. Films are Plus-X, TMX and TMY.

I see you are doing E6. Is there the possibility the chemistry vendor has changed the chemistry without saying anything? Have you tried a different E6 chemistry? Some chemistry/film combinations are known to work badly in drum processing -- they may have changed your E6 formulation so it is now one of them.

Obviously, something changed ...

Yes I agree, obviously something changed.

The premise is that the blotching is caused by the film touching during dev and therefore the chemicals not getting to that area. This is confirmed by the reduction to 4 sheets as they are physically more separated.

So to me this rules out chemicals. (I use the kodak single use chem kit).

What has changed is
--the re-introduction of Velvia 50
--I have added Provia
--I moved to a much more humid climate

My first suspicion is that the acetate based changed on the Fuji films and is now more flimsy causing the film to flex during the rotation and then stick together.

Of course this is pure speculation, I don't have any specs on this.

Quote:

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Originally Posted by Todd

Yes I agree, obviously something changed.

The premise is that the blotching is caused by the film touching during dev and therefore the chemicals not getting to that area. This is confirmed by the reduction to 4 sheets as they are physically more separated.

So to me this rules out chemicals. (I use the kodak single use chem kit).

What has changed is
--the re-introduction of Velvia 50
--I have added Provia
--I moved to a much more humid climate

My first suspicion is that the acetate based changed on the Fuji films and is now more flimsy causing the film to flex during the rotation and then stick together.

Of course this is pure speculation, I don't have any specs on this.

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Sounds to me that you loaded the sheets incorrectly. I suggest that you take some practice negs and practice loading in the daylight. Note very carefully how the shyeets are spaced in the reel and the surrounding structure so that you can confirm that each sheet is inserted correctly in the dark. Also, note carefully the surrounding structure where the wings are placed.

I prefer to develope B&W by hand and always use a 2500 Drum and 2509N reels without problem with 6 sheets.

Thomas

Well, as I mentioned, I bought a new tank and set of reels. I just finished processing with the new set and...bam! Perfect results (again). I plan on buying 2 more new reels to replace the older ones so it looks like I will be back to 12 negatives here soon.

By the way the new ones are the N version but I can't tell if the old ones are.

Thanks for all the suggestions.