Hello,

After longer time of using Pyrocat HD as my main developer I got recently problems with uneven development with Jobo 1520 drum with inversion agitation.

Let me first describe my development procedure then I will post some samples:

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- I develop two 120 films on one reel inside the JOBO 1520 drum. I do use thatlittle plastic piece to avoid accidental overlapping of films

- Films I hve developed concern Ilford Delta 400, Delta 100, FP4+. Apart from slightly longer development the procedure for Delta 400 is very similar to that of Delta 100 and FP4+.

- Please note - all these photos were taken with Mamiya 6 what implies that top part of the image was pointing to the top of the JOBO drum what means that what is horizontal on film was horizontal inside the drum as well.

- Development temperature is mostly 21 degrees Celsius and I do take care to keep the temperature of subsequent liquids within 1 degree.

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Development for fp4+ and Delata 100 films (I use the same times):
1) 4 minutes prewash in clean water
2) Pyrocat HD 1:1:100, 500 ml, 9 minutes total time, inversions first 45 seconds than 4 inversions at the end of 3 and 6 minute.
3) 4 minutes water stop - inversions first 60 seconds than every minute a few
4) Ilford fixer (1:4) 10 minutes - inversions every minute
5) 10 minutes was using the JOBO hose (so it is continuos)
6) 1 minute in Photo Flo
7) hang over night to dry (in our bathroom)

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My questions:

1) this looks very much like insufficient agitation. I did use 4 inversions every minute in the past and got better results, but I would prefer the 3 minute intervals. Should I do more inversions than 4 per agitation interval to avoid this problems?

2)Many use semi stand method with Jobo drums - do I do anything else than agitation wrong?

3) What is your approach with Pyrocat HD and Jobo drums? Should I change times or dilution or .. ? I would be interested to use a slow motor base, but none on them market are built for drums as small as Jobo 1520.

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Now the samples:

Please note that there are large versions on flickr if you click on the images. The full series is HERE (5 more images than linked below).

I am showing the worst ones here, but most of these films have slightly darker top and bottom edges with fine structure.










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Your help will be much appreciated ...