B&W King 5x7 tank processing issues - help me solve them!

[Fred L]

if you wanna borrow it to try out, you're more than welcome. I keep one at the gallery, and one at home. guess you'll need my roller base well. for multiple sheets the 3006 can't be beat (although tray adherents believe otherwise haha)

[landstrykere]

thought about ordering B's 5x7 reel which fits in a Paterson tank, but wonder if that won't be more of the same.

do you have a 1L steel tank for 35mm/120 spirals? I occasionally do 4 sheets of 5x7/13x18/half-plate in a Kindermann. Inversion agitation only obviously, soft.. Four sheets are hold tight by themselves, no rubber.




sometime I also was considering, beside the chinese tank you have, a canadian plastic spiral. It uses a middle holder too, and this may have been the cause for same issue you experience:
https://www.largeformatphotography.i...era-s-5x7-reel

the spiral in my former link doesn't use middle rail to hold the sheets and takes 5 sheets. But requires Jobo 2500 tank and so twice the volume in case of inversion.

in your case as I understand amount of sheets processed at a time is what matters. BW King spiral takes 6. Bounet, 20th Century take 4. Jobo Expert Drum takes 6. The Jobo is very expensive, in the 600€ from Fotoimpex who resells from manufacturer:
https://www.fotoimpex.com/darkroom/j...expert-10.html

Large format is either about money or about tinkering, and tinkering is typically dismissed.

That said I recall threads somewhere about the 5x7 BW King with many satisfied comments.

[Alan9940]

Alan...anything more you could tell us about using this tank for EMA? Thanks!

Would love to be able to process six EMA films at once!

It's really not that different from using the homemade tanks Steve has you build, except you're not rolling it.

Here's what has worked for me with 4x5 Fomapan 100 and Pyrocat-HD: 6ml part A + 4ml part B + water to bring the total volume to 1,050ml. All solutions at 70F. 5 min water pre-soak, 2 mins initial agitation (inversions), then 6 x 3(20)--tank sits for 6 mins with 20 secs agitation between each cycle. Therefore, total development time would be 20 mins.

I do use homemade tanks, too, for single sheets but found that the agitation cycle needs to be slightly shorter rest time followed by slightly shorter agitation time. I'm guessing that the rigorous agitation (rolling) of the homemade tanks vs the B&W King tank demands a somewhat shorter overall development time.

[Fred L]

another alternative, and one I haven't tried, is using the more common Jobo 3010 tank. It's meant for 4x5 film but I checked the fit and 5x7 fits in the chamber. There are two ridges that may or may not affect the backside (I don't believe it will but best to confirm).

Pricing is same as 3006 so no cost savings really. fwiw, the gallery has a 3010 under the processing sink, rarely gets used afaik.

This is a thread on LFPF about this combo.

https://www.largeformatphotography.i...JOBO-3010-drum

[landstrykere]

btw, about the Expert drum, the small presentation from the manufacturer shows what it is about.
It is just even (by motorization) rolling agitation of 5 (3006) or 6 (3010) small cylinders that are inside a drum. The processor fills the drum with the liquid, and it's emptied by lifting the tank.
The sophisticated point is temperature control done by water circulation through openings at the bottom, inside the inner chamber of the drum, around each cylinder, with the tempered water in the processor bench.



the water circulation, not easy to reproduce, otherwise one can use tubes of appropriate dimensions, insert then in some drum, hack a light sealed refill/empty top with a cone and the lid of a Kinderman tank. This is one of the many hacks I had in mind, but then 4 sheets of 5x7 inside a 1liter Kindermann tank (the one taking 3x 120 spirals) as pictured earlier works most of the time.

Here an Expert drum implementation with a paper sheet drum:

https://forum.mflenses.com/diy-jobo-...um-t28961.html




if you follow JOBO process in an orthodox way the CPE-3 or CPP-3 is required. Many people just do without the CPP and its water temperature control, but just some roller. But then if no water circulation inside the inner chamber of the drum, no need for the drum itself, and any tinkering like the one there with a print drum would do... :-)

the 4 sheets in the Kindermann are easily temperature controlled .... by immersion in the kitchen sink filled with water, in case developing time is long. Typically I try to keep the temperature in my flat at 19 to 21 Celsius anyway.

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that said, if others have success with BW King tank and spiral, they you could too. It's about finding old threads somewhere.