BTZS Tubes/Pyrocat Quantity Question

[Richard Wasserman]

After recently developing a problem with uneven development using a slosher I have decided to give BTZS tubes a try. I am a bit unsure though about how much Pyrocat to use. The caps seem to hold 60ml easily, but that seems like possibly not enough for good results. What do you BTZS users do? Also do you presoak—I assume yes.

[fishbulb]

60ml is the recommended amount for BTZS tubes. Since it's basically continuous agitation (rolling the tubes in the water) you don't need a lot of developer.

I recommend watching the BTZS youtube videos if you haven't yet. They are very helpful.

4x5 part 1: https://www.youtube.com/watch?v=TMXQO5ATgiY
4x5 part 2: https://www.youtube.com/watch?v=l_KGv_SqbzU
8x10 tubes: https://www.youtube.com/watch?v=p0WaDVDAXLM

[Roger Thoms]

In looking at my notes, I have been using Pyrocat HD @ 1:1:100 in 4x5 BTZS tubes with no problem. I also presoak, which is a bit of a pain as my darkroom is a closet and my kitchen. It would be great to hear if anyone is using Pyrocat HD and BTZS tubes without a presoak. Or maybe I should just try it.

Roger

[Richard Wasserman]

I've watched the videos, thanks. Fred Newman suggests 60ml which seems like a very small quantity, but I read somewhere that Sandy King says to use 75ml which seems like a tight fit and possibly trouble prone—splashing, etc. I haven't tried the tubes yet and I of course need to play around with them to figure out what works best for me. I'm just curious what other BTZS/Pyrocat users are doing.

[Jim Noel]

Anything less than 75mm per 20 sg. in. of film is likely to lead to developer exhaustion thus underdevelopment. This may become even more evident with N+ and N++ development.

[Kirk Gittings]

Richard, yes 60 ml works fine for the neg I want with PC 1:1:100 (4:4:400 actually for 6 tubes with a bit left over)-and fine for +1 (75ml won't fit in the cap and you don't want to fill them right to the lip for reasons you said-Sandy I think uses homemade tubes which will hold more maybe). But I am looking for a slightly flat negative. Haven't tried it for +2 in so long I'm hesitant to suggest it-might want to go to la stronger dilution for that). You could always vary the dilution to get the strength you want for N in 60ml. Mix it right before use as it oxidizes fairly quickly. I do not do a presoak. I have a hard time juggling 6 of those puppies for the initial agitation so I invented this caddy>



http://www.largeformatphotography.in...for-BTZS-tubes

[Richard Wasserman]

Thanks Kirk! I developed a run of 4 sheets just to prove the concept and all went well. I filled the caps to where the internal thread starts, which used about 65ml—Hey,every little bit helps. I used a presoak which I found not to be too difficult, although with 6 tubes may be trickier. I'm going to expose a few sheets of the sky to test for evenness of development and will try not using a presoak to see if that makes a difference.

I bought the parts to make a caddy which looks to be very useful. BTW, I found what are called Repair Couplings which don't have the internal ridge that would have needed to be removed. They cost about $1.00 each more, but will save the time and effort of filing and sanding down the separator.

[Kirk Gittings]

Cool. Repair couplings! Never thought of that-perfect!