I just re read my post and I did not mean it to sound so harsh. Forgive me pls.
No problem with me. I skimmed the post and did not catch the most relevant part.
Originally Posted by lee
I scanned the affcted negative. Here is my problem. Also here is how I do load the film. I must admit, however, I did not pay too much attention to how deep in push the film into the tube. Sometimes the film edge was not exactly parallel to the edge of the tube. I posted the same question to largeformatphotograpy.net forum and got the advice that this may be crucial, which I did not realize. So sometimes my film was certainly loaded not exactly as shown.
well, looking at your negative example, the perfectly clear edge with the even line looks like it is supposed to look. If you are getting that inconsistently, I'd check your method for loading your sheet film holders for consistency. The wierd blob on the negative looks like some kind of developer drip. That could be caused by either the filling method (since it is an Expert drum being used off a Jobo processor, you'll have that issue with filling while the drum is not rotating) or you aren't cleaning your drum carefully enough between batches, and the film is sticking to the wall of the drum and trapping chemistry between it and the drum wall, causing the overdevelopment spot. You need to double-check to make sure you are loading the film in the drum emulsion side IN, not out.
Loading an Expert Drum
Definitely what has been said makes sense ( especially facing the emulsion the correct way ). Here's a snapshot regarding loading the film - pushing the film too far in can cause negatives not to clear properly. While the photo here shows a 3010, it could be the same issue for the 3006.
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Could it be that the rotation is too fast and shifting the film so that during one stage of processing the film is in one posisiton and another stage it is in a different position which prevents it from getting chemistry?
There are areas on the bottom part of the negative, usually right next to the edge, which seems to receieve no chemistry. Strikingly, sometimes they clearly received developer but did not get the fixer.
I can't remember what the actual speed is for the 50 setting on the jobo (the proper setting for expert drums), but I bet it is 50 rotations per minute (maybe someone else remembers)
Or the rotaion could be too slow, thus not distributing the chemicals through those tight spots in the expert drum sufficently.
Or it could be somehow related to how you pour each chemical into the drum? That would certainly accout for consistency issues. Also, how long is each chemical in the drum. Because of unexplainable problems I've moved to 2 minutes of stop bath and had no problems since????
I would try and use more chemicals...
Also, I would appreciate a scan of the entire peice of film, I can't even tell what the problem is from the picture you uploaded.
I hope this helps, but I'd love to see the whole piece of film.
Looking at the negative example, it looks to me like perhaps the tube wasn't properly dried prior to putting in the film.
FWIW, I use all my Jobos with a Unicolor drum and take the drum off the rollers when changing chemicals. This is because I don't do my developing in a bathroom. I've typically been doing it where I have access to a tv/computer and I don't want a mess from the chems if I can help it. I think maybe I've had problems with some swirl marks on possibly one neg (haven't printed/had it printed so I can't be sure) in the last couple of years (knock on wood). I don't load the Jobo completely with film though either.
Thank you very much for your input. I really learned a lot from here and from the same question I posted to largeformatphotography.info forum. I think I identified following problems:
1. accidental wrong film loading
2. not enough chemistry added (I will increase to at least 500ml)
3. wrong technique of drum filling
I do not think that the problem has to do with drum drying as I usually process films only once in a week, it has enough time to dry completly. I also use the sponge to dry the tubes.
This may well be that my setup is particulary prone for wrong film placement because the drum rotation is much slower then recommended by Jobo. Jobo recommends 50rpm and my motor base gives only 15rpm. On the other hand PyrocatHD instructions recommend much slower rotation then specified by Jobo. I think that combination of above factors actually causes my problem.
BTW - do you think that increasing the pyro developer volume will help to decrease oxidation rate during drum processing? It seems resonable as there would be less air in the drum and also volume/surface ratio would be better.
Once again I want to convey my apperciation for your time and help.