Originally Posted by
Doremus Scudder
I see no reason why the tray life of chemicals should be different from small to large. There's no reason to use print processing chemicals one-shot if you're using volumes such as you suggest. It's both wasteful and uneconomical.
I use Bromophen (indeed a print developer), Liquidol and scratch-mixed D-72 for the most part. All of these last a printing session, i.e. a six to eight-hour day. 4-5 gallons of Bromophen will develop a square mile of photo paper! Don't toss it after one or two prints.
Stop lasts a couple of days when I'm printing heavily (2 liters in a 12x16 tray for 11x14 prints or 4 liters in a 16x20 tray for 16x20s). No reason to use your stop bath one-shot. Siphon it off into a container and reuse.
I use fixer two bath and run 36 8x10s through a liter of bath one before changing (that conveniently works out to 36 11x14s per 2 liters and 36 16x20s per 4 liters). I use Ilford Rapid Fixer or Hypam 1+9 (more economical) and fix for 1.5-2 minutes each bath. I mix both bath fresh after five cycles maximum. Same as above for re-use.
Hypo clear is the same as the recipe Pere gives above simplified: 1 Tbsp sodium sulfite plus a pinch of bisulfite (or metabisulfite) per liter. Without rinsing I get 36 8x10s per liter capacity. You can scale that capacity up for whatever size prints and volume of solution you like. Really econonmical
I selenium tone and filter and replenish the toner. It lasts forever that way. When toning times get too long, a dash of concentrate restores activity. Keeping 4-5 gallons of replenished toner around shouldn't be that hard...
I transfer prints directly from the second fix to the toning bath and directly from toning bath to hypo clear (hence the reduced capacity noted above, but worth it for me not to have the extra rinse step). I usually wash and dry my prints after fix one, choosing just the real keepers for a later toning session. These then get a pre-soak, fix 2, toner, hypo-clear and wash.
All this is really economical. I see no reason why you couldn't adapt something like this for your large trays. If you have room for four trays you've got a production line that looks like this: Session 1 (printing) - developer - stop - fix one - water soak/wash. Session 2: - soak, fix two, toner - hypo clear and then back into the water soak tray for wash. I could imagine doing several prints a day for session one and then collecting the best from several days work to do a session two with.
If you have room for fewer trays, you'll have to siphon off the chemistry and save it between steps. I could see a two-tray system: developer in one tray, then transfer to the stop. After a minute, drain and save the stop and pour in fix one. After fixing time is up, pour off the fix and add water. The developer is the only step that is hugely time-critical, hence the separate tray for developer.
Or, if you want to go with one tray, you could reduce your solution volume. Do brush developing with just enough developer to cover the print. Dump this and pour in a small amount of stop after time's up, using another brush. Dump that and fix using a weaker fixer (1+9 or greater). Using fixer one-shot enables you to use fresh fix every time and therefore two-bath fixing is not needed. You do, however, have to test your workflow to find the right volume of fixer and the optimum fixing time using the ST-1 or selenium-toner tests for residual silver. Once you have established that, you can add a fudge factor and feel confident in your fixing regime.
Hopes this helps,
Doremus
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