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  1. #1
    DeanC's Avatar
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    Lifetime of Pyrocat-HD working solution

    Does anyone (this probably means Sandy ;-)) know how long Pyrocat-HD lasts after mixing?

    I do all my film developing in Jobo expert drums and I'm wondering if it'll last long enough for me to mix up a big batch, develop, stop, fix, rinse one set of negatives, rince and dry the drum and then repeat on another set. If it will, how many sets can I reasonably get through? With the small quantities of sols. A & B involved (even at 2:2:100) it seems it would be easier to accurately mix up a batch that is a litre or two in size than to mix a few that are each 200-500ml.

    Thanks,
    Dean

  2. #2

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    I develop my film in BTZS type tubes with minimal agitation. That means that I have a large volume of developer in an 8X10 tube. My experience indicates that I can develop 3 negatives with the same developer reused. This often amounts to over two hours of combined development time when I am developing a SBR 5 or SBR 6 negative. 10 oz of working solution Pyrocat at 1-1-100 will accomodate an 8X10 negative. The 1-1-150 (minimal agitation) and 2-2-100 Azo or Pt dilution should certainly have the same capacities. Hope that this answers your question.

  3. #3

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    I have mixed a batch (500ml of 1:1:100) and had to leave it standing in a closed bottle for 2.5 hours with no depreciation in quality. The liquid did discolour slightly (tan) but still worked fine.

    Phill
    It is not tradition that secures the survival of our craft, its the craft that secures the survival of our traditions.

  4. #4

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    Just for interest sake my Pyrocat-HD stock solutions have given up the ghost but lasted 8 1/2 months in sealed medicine bottles. These bottles were opened at least once per week for removal of liquid. Worked fine last week but completely dead this week with only approx 10ml left.

    Phill
    It is not tradition that secures the survival of our craft, its the craft that secures the survival of our traditions.

  5. #5
    roy
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    [QUOTE=philldresser]Just for interest sake my Pyrocat-HD stock solutions have given up the ghost Worked fine last week but completely dead this week

    I hope Phil, you did not find out with film in the soup. If you did not lose any exposures, what was the test ?
    Roy Groombridge.

    Cogito, ergo sum.
    (Descartes)

  6. #6

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    [QUOTE=roy]
    Quote Originally Posted by philldresser
    Just for interest sake my Pyrocat-HD stock solutions have given up the ghost Worked fine last week but completely dead this week

    I hope Phil, you did not find out with film in the soup. If you did not lose any exposures, what was the test ?
    Stock Solution A is good until it turns dark brown or black, and this appears to happen quite suddenly after about six months if there is only a small amount of solution left in the bottle. Full, or even partially full bottles are good for much longer, up to a year or perhaps even more. In any event my experience is that the solution is good as long as it is clear. Stock Solution B should last indefinitely.

    Contamination of either Stock Solution A or B with minute quantities of the other will greatly accelerate aging and decrease the shelf life of the solutions. Therefore be especially careful when mixing the working solution to avoid contamination. I use dedicated syringes for each of the stock solutions.

    However, if you are concerned about maximum shelf life consider mixing Stock Solution A in propylene glycol, a la Pat Gainer.

    Sandy

  7. #7

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    Quote Originally Posted by roy
    I hope Phil, you did not find out with film in the soup. If you did not lose any exposures, what was the test ?
    Roy

    I ran half an erroneously exposed sheet of 5x4 in a btzs tube. Came back very clear indeed. Mixed up a new batch and ran the test again and it was very black indeed. Not very scientific I'm afraid

    Phill
    It is not tradition that secures the survival of our craft, its the craft that secures the survival of our traditions.

  8. #8

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    Quote Originally Posted by sanking
    Stock Solution A is good until it turns dark brown or black, and this appears to happen quite suddenly after about six months if there is only a small amount of solution left in the bottle. Full, or even partially full bottles are good for much longer, up to a year or perhaps even more. In any event my experience is that the solution is good as long as it is clear. Stock Solution B should last indefinitely.
    Sandy

    My solution A was a light brown and produced no density at all on a fully exposed sheet of 5x4 (1:1:100@20c 8.5min). A fresh batch worked fine. Could it be that I put 2x solution B or A in the mix ? I am usually quite methodical with chems but I did mix up a batch in my fixer last week. Fortunatly I saw the error.

    Phill

    PS I was quite impressed with the 8.5 months
    It is not tradition that secures the survival of our craft, its the craft that secures the survival of our traditions.

  9. #9

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    Quote Originally Posted by philldresser
    Sandy

    My solution A was a light brown and produced no density at all on a fully exposed sheet of 5x4 (1:1:100@20c 8.5min). A fresh batch worked fine. Could it be that I put 2x solution B or A in the mix ? I am usually quite methodical with chems but I did mix up a batch in my fixer last week. Fortunatly I saw the error.

    Phill

    PS I was quite impressed with the 8.5 months
    Phil,

    If you put double B or A in a working solution I doubt you would be the first person to do that. I am dumb enought to have killed more than one good negative that way.

    But I suspect that may have happened in your case if you got absolutely no devloper action from the mix. A light brown mix suggests that oxidation is taking place and would probably give weaker results, or perhaps more staining, than a clear solution, but I don't think it would be totally dead.

    Sandy

  10. #10
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    As Sandy said, if you can't use it before it spoils, mix it in propylene glycol instead of water. All you need is the phenidone and the catechol. The bisulphite is for preservation. Glycol does that. If you think you need sulphite for some other reason, add a little to the working solution or to the B solution. Don't use very much, or you will lose the stain. Phenidone and catechol with sulphite and alkali is not much different from an ordinary PQ developer. The working solution should have no more than about 1 gram for every gram of catechol. That much will assure the superaditivity of the catechol with the Phenidone.

    I find I can get good stain and tanning as well as good film speed without any sulphite.
    Gadget Gainer

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