A couple of practical concerns about storing chemistry in trays

Discussion in 'B&W: Film, Paper, Chemistry' started by Anupam Basu, Feb 18, 2007.

  1. Anupam Basu

    Anupam Basu Member

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    Until recently my 35mm darkroom was in a shared bathroom and I had to bottle all the chemistry up once I was done. But now that I have a more permanent setup in the basement, I sometimes feel too lazy to pour everything back into the bottles after every session. I know that I don't have much choice with the developer and fixer too will go bad if left exposed over a long time. Even with stop bath, evaporation remains a problem.

    So I am wondering if anyone has any practical tips or tricks to keep chemistry relatively fresh in trays. One interesting idea I found was to float another tray of the same size on the chemistry. I must try that, but before I buy new trays, any opinions on that or other ideas?

    Thanks,
    Anupam
     
  2. pentaxuser

    pentaxuser Subscriber

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    I have seen tips such as covering the trays with clingfilm but the real problem is that this still leaves a large surface area over which there is air.

    I suspect that the best solution may be to use up the developer tray's contents with sufficient prints and then dump. Mind you if you are dumping then it still leaves the problems of setting up again.

    "Vertical trays" in the form of slot processors such as Nova certainly do work but are more expensive and need to to be left in situ.

    I don't think there is any real long term solution with trays but it may be worth covering with cling film, having given a quick burst of Protectan over the liquid and using a replenishment system. That way the replenishment rate and frequency of use, say every night or every couple of nights may just keep the developer fresh enough.

    Maybe worth a try. If the developer has deteriorated over 24/48 hrs the first print will reveal this and you've lost one print only to test the idea.

    pentaxuser
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    One liter of working strentgh Dektol in a tray with a saran wrap cover will keep for several days depending on use. Stop and fix will keep for a week or more under the same conditions, and longer if replenished.

    After a day or two, you can increase development time and the Dektol will snap right back. So, if you used 1' development time, by the end of a week of moderate use, you can probably get by with 1.5'. This works, but I would not suggest you do it for absolutely critical work.

    Most other developers keep rather poorly compared to Dektol.

    PE
     
  4. PHOTOTONE

    PHOTOTONE Member

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    Lots of b/w darkrooms over the years have had a deep hypo tray that holds a couple of gallons of fixer. In this situation it can last for weeks. Evaporation is your only enemy in this regard. When I printed bw regularly, I used to always keep the fixer (deep tray), and dump the stop and developer after a day or two. Of course eventually I would replace the fixer also.
     
  5. PHOTOTONE

    PHOTOTONE Member

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    Once diluted to working strength and used some, paper developer such as Dektol probably shouldn't be saved back into a bottle as it will still have a relatively short life (days). Best to just keep it in the tray as PE mentioned and use it for a few days in succession, extending your developing times.
     
  6. jstraw

    jstraw Member

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    I think a lot of people get confused about using Saran wrap on on trays. You don't stretch it across the lip of the tray, you float it right on the solution to prevent contact with air.
     
  7. Bob F.

    Bob F. Member

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    Rather than put the clingfilm over the tray, float it on top of the liquid; as long as it is wider than the tray you can "tuck" it along the sides and make a reasonable seal. I've had Ilford Cooltone developer in a 2 litre jug sealed in such a way for nearly two weeks now and I just used it and it is fine. I also use a Nova vertical tank system and they keep fixer OK for well over a month even with a few square inches of surface area. Some developers last longer than others so I would not treat that as a general recommendation, but it does suggest that fixer in particular can withstand some mistreatment beyond that usually recommended. I always test the fixer with a clearing test and Tetenal fixer test strips (tests for silver content and pH) before use to be sure.

    Cheers, Bob.
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    It actually does not need to float on the liquid. You can put it across the top of the tray. All that is needed is a method to prevent air currents from passing over the developer. Saran is somewhat air permeable IIRC. It is the air currents that lead to oxidation and evaporation and even at the top of the tray, it helps a lot. I've found the other way to be messy.

    In fact, I have 3 large rigid plastic sheets to cover my trays and they do a pretty good job themselves.

    PE
     
  9. dancqu

    dancqu Member

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    Some consider bottling and washing up WORK.
    I practice a variation of rotary processing. Rather
    than A tube and one shot chemistry I use A tray
    and one-shot chemistry.

    No more used chemistry to save and fresh
    chemistry each print or few. Dan
     
  10. Mike Té

    Mike Té Subscriber

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    Dan, I consider MIXING chemicals to be work as well!

    :smile:

    Cheers.