7x17 Rotary development issues

I thought I had got a handle on my Rotary development of 7x17 but obviously it would appear not...

I'm using a JOBO 2850 and a simple roller base made from roller wheels. I rotate very slowly in random amounts with frequent sideways sloshing of the developer. I use 750ml of developer for 2 sheets of 7x17. The JOBO 2850 had lengthwise ribs that hold the sheets in place, but have a gap in these ribs where the two tubes join. The main streak is caused by this and I thought I had reduced this to minimal. The other streaks I have not noticed before, but that might be due to not shooting scenes with large areas of flat tones.

Given this I don't think the 2850 is worth pursing, but with out access to a darkroom I'm rather stuck unless anyone had any idea how to improve this or another method of daylight developing 7x17 sheets?

Thanks in advance.
Andrew


10 year expired Ilford HP5 in Moersch Finol 1+1+75 (750ml)

Expired film and staining developers are not a good match... You might want to try a different developer. Something that doesn't stain. I am guessing that your problem mostly lies there. And increase the amount of developer. You might want to try a dilute developer like Rodinal, and again, increase the amount of developer you use. 750ml seems an awfully small amount for two sheets of film that large.

Staining developers are often reported to cause trouble in Jobo print drums with ribs. Try a non-staining developer - I've gotten clean results with ULF sizes of HP5 Plus in the 3062 and 3063 drums with D-76.

The Jobo drums give a minimum volume for one-shot print development, but that is usually low for film developers that are less concentrated (generally).

My experience doing 8x10 in print drums is that a) make sure the drums are completely dry inside before loading them. A drop of water running around pre-development will show up, and b) make sure the drum is completely level when it is on the rollers. If you are using a multiple segment drum assembly, make sure all the segments are fully seated - a 'bent' assembly will cause standing waves.

If you load a sheet the opposite way (but still emulsion towards the centre), are the density marks in the same place compared to the end of the drum?

If the marks are due to different turbulence around the join in the locating ribs, my first suspicion would be insufficient solution.

I'd start with 1 sheet at a time (ideally of non expired film) in a non staining developer - even with D-76/ ID-11 at stock strength, you may be looking at a minimum volume of 350ml or so to be hitting the correct sensitometric aim for the given times. There's really very little point in using staining developers if you learn how to usefully manipulate the sensitometric behaviour of the film.

User jp80874 used a Jobo drum for 7x17 many years and got excellent results. Off hand I can't find his description of how he did it, maybe it is on LF forum website (same user name I believe).