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  1. #1

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    Three Pyrocat HD/PMK Questions

    1. Does Pyrocat HD require the the 'long' washing times, similar to PMK (30+ minutes)? Or is the standard 10/15 acceptable?

    2. What is the shelf life of open containers of Sol A and Sol B?

    3. Any preference/recommendations between Pyrocat HD or PMK for HP5+ 35mm that will may be enlarged to 11x14, perhaps larger? (yes, I know that is stretching 35mm a bit)

  2. #2
    Eric Rose's Avatar
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    1. I use 15 to 20 minutes, but that is the same times I use with HC110 too.
    2. I have used sol's A&B that were at least 1 year old with no problems.
    3. I have found PC-HD to give me very nice 11x14's from 35mm. I've never used PMK.
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  3. #3

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    jtsatterlee

    1. I have found Wash times of 10-12 mins and a HCA bath for a few mins is sufficient on FP4
    2. A solution lasted me 10 months - B will last indefinitely I believe
    3. Same as Eric 11x14 from FP4 in 35mm are no problem with Pyrocat

    Phill
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  4. #4
    bmac's Avatar
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    How are you guys sure a 10-20 min wash is enough? I wash at least 45 mins in an archival washer (sheet film).
    hi!

  5. #5

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    Quote Originally Posted by bmac
    How are you guys sure a 10-20 min wash is enough? I wash at least 45 mins in an archival washer (sheet film).
    Brian

    I'm not sure that i,m sure but I am following the dev instructions from Sandy King where he states :

    Presoak film for two minutes. Use a plain water stop bath for one minute. Use an alkaline fixer (rapid fix without hardener) for 5 minutes. Wash in running water 10-15 minutes.

    Admittedly I sometimes wash for longer (normally while I am developing the next film/sheet) but I add the HCA wash as well and then rinse for a further 5min.

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

  6. #6

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    Quote Originally Posted by bmac
    How are you guys sure a 10-20 min wash is enough? I wash at least 45 mins in an archival washer (sheet film).
    With film a 15 - 20 minute wash after fixing in a non-hardening fixer should be adequate. Except for the initial rinse off, film washing is primarily a diffusion process, so washing in multiple water changes is a very effective and water efficient washing method.

    If you are not certain that you have gotten the fixer out of the film, perform a residual fixer test after washing.
    Tom Hoskinson
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  7. #7

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    Quote Originally Posted by jtsatterlee
    1. Does Pyrocat HD require the 'long' washing times, similar to PMK (30+ minutes)? Or is the standard 10/15 acceptable?

    2. What is the shelf life of open containers of Sol A and Sol B?

    3. Any preference/recommendations between Pyrocat HD or PMK for HP5+ 35mm that will may be enlarged to 11x14, perhaps larger? (yes, I know that is stretching 35mm a bit)

    Films need much less wash time than papers because all of the chemicals that need to wash out are right on the surface in a thin layer of gelatin. However, wash time is less important than the total number of changes. Ilford, for example, recommends a system that is based on twenty changes of water, without any running water at all. However, with a good flow of water entering at the bottom of a tray and leaving at the top you should easily get more than 20 changes in a 10-15 wash.

    As for shelf life, Solution B lasts indefinitely. Solution A, in a container that is at least half full, should be good for up to a year. If you need longer shelf life consider mixing Solution A using one of the glycols or glycerin, as Pat Gainer has suggested. I have mixed the Pyrocat-HD Stock A solution in both propylene glycol and glycerin and the results were identical to mixing in water. Stock A mixed in either glycerine or glycol will have a shelf life of years and years. If you are interested in this mix as follows.

    1. Heat the glycol or glycerin to 250º F. A liter of either solution heats to this temperature in about one minute in my microwave.

    2. Add the chemicals to the solution at 250º F in this order: First, pyrocatechin, then sodium metabisulfite, and then bromide.

    3. Allow the solution to cool to about 150º F and then add the phenidone. The phenidone will break down if added to the solution when it is over 200ºF.

    Sodium metabisulfite is used in the Stock A solution when mixed with water to acidify the solution and it functions as a preservative. It also reduces staining slightly because when mixed to form a working solution plain sodium sulfite is formed. You obviously don't need it in glycol or glycerine as a preservative and some people, Tom Hoskinsoin being one of them I believe, have simply omitted the sodium metabisulfite with the glycol solution and report good results with apparently no additional staining. I have never gotten around to testing staining with and without the soduim metabisulfite in the solution mixed with glycol so I am still adding it when just as I do with water. It may not be necessary, as Tom reports, but then again so little is needed and my current supply of sodium metabisulfite should last for at least two more decades, so what the hell!!

    Another variation is to add the bromide to the Stock B solution rather than put it in the Stock A. This will make no practical difference so long as the ratio of Stock A to Stock B in the working solution is 1:1. This may be a better solution since bromide is hard to get into solution in glycol, even at 250º F.

    Be very careful when mixing solutions over 250º F. A spill on the skin at this temperature can do great damage, as you might well imagine.

    Sandy
    Last edited by sanking; 11-11-2004 at 04:39 PM. Click to view previous post history.

  8. #8

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    thanks to all for the information

  9. #9
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    I have used both PMK and Pyrocat and I would recommend only Pyrocat for 35mm if you wish to use a staining developer for this format. I have not been happy with staining developers in 35mm - if you plan to enlarge past 5x7. I would prefer a "fine grain" solivent developer for 35mm for enlarging.

  10. #10
    DeanC's Avatar
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    Quote Originally Posted by sanking
    Sodium metabisulfite is used in the Stock A solution when mixed with water to acidify the solution and it functions as a preservative. It also reduces staining slightly because when mixed to form a working solution plain sodium sulfite is formed. You obviously don't need it in glycol or glycerine as a preservative and some people, Tom Hoskinsoin being one of them I believe, have simply omitted the sodium metabisulfite with the glycol solution and report good results with apparently no additional staining. I have never gotten around to testing staining with and without the soduim metabisulfite in the solution mixed with glycol so I am still adding it when just as I do with water. It may not be necessary, as Tom reports, but then again so little is needed and my current supply of sodium metabisulfite should last for at least two more decades, so what the hell!!
    I just tried mixing up my first batch of Stock A in propylene glycol and ran into a slight problem. It seems that neither the sodium metabisulfite nor the bromide would dissolve completely for me. I heated the glycol to 250F on a stirring hotplate and added the chemicals in the catechol, sodium metabisulfite, bromide order. The catechol seemed to go into solution readily but the metabisulfite left clouds of undesolved reagent floating in the solution and I still have a couple of lumps of bromide in the bottom. I used 750ml of glycol, 50g of catechol, 10g of sodium metabisulfite, 2g of potassium bromide and 2g of phenidone and topped things off to 1000ml at the end.

    I'm going to try again tomorrow, I think, perhaps leaving out both the sodium metabisulfite and the potassium bromide. If I do that, will I still need to heat the glycol to 250F to dissolve the catechol?

    Quote Originally Posted by sanking
    Another variation is to add the bromide to the Stock B solution rather than put it in the Stock A. This will make no practical difference so long as the ratio of Stock A to Stock B in the working solution is 1:1. This may be a better solution since bromide is hard to get into solution in glycol, even at 250º F.
    This may be a silly question, but... Will moving the bromide to the Stock B solution impact its storage life in any way?

    Thanks,
    Dean

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