I have processed 4 x 5 sheet film in a Jobo CPE 2 processor for ages. TRI-X in HC110 and sometimes D76. Just recently noticed I was gettin some edge density on the negs that are on the outside of the reel. It is not an Expert drum but a reel that holds 6 sheets. Different rotation times don't change anything except the overall density.
Any clues from anyone who can help. Thanks, Richard
There are "newer" reels (I believe called 2509N ?) which utilize two black plastic inserts which are placed 180 degrees from each other on the outskirts of the reel after sheet films have been inserted. They were created by Jobo to promote more even development with this particular reel type.
Are you already using these?
Richard
Do these densitys show up dark on the image following the rotation of the drum?? Almost like road ruts running through the image,
If so we had this problem , and tried over thirty different solutions to solve the problem
Finally solved the problem by taking the drum off the machine and hand rotating the drum, in the first 10-50 seconds of development. All marks gone
We know this is not convienient and in our history this problem only occured with 120 film .
Try this first ,as you may have a long series of trial and error to solve problem,
If the plus density marks mimic the edges of the film , then the problem may be laminar flow. Are you using distilled water??
regular tap water can actually be the problem, by not allowing the developer to flow evenly and quickley over the film.
The first 30 seconds of development are the most critical and if not done correctly .We have seen all our problems during this period,
I agree with Bob. Use a 5' distilled water pre-soak, and also use distilled water to mix up your developer - always.
It sounds like your edge density issues are indeed from the Jobo spinning at too high a speed. Make sure you have it on the slow speed, or process by hand rotation.
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