Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,868   Posts: 1,583,288   Online: 1116
      
Results 1 to 3 of 3
  1. #1

    Join Date
    Jun 2004
    Shooter
    Multi Format
    Posts
    145
    Images
    2

    Pyrocat HD recipe help!!

    I've been doing a whole lot of testing with Pyrocat HD in a Jobo processor. I've just noticed, while mixing up the latest batch of chemistry (which I purchase from Photographer's Formulary) that there appears to be some discrepancy with the actual make up of the part B solution - all of the original publishing of the formaula I can source suggest that the Part B solution is now a 100% solution of Potassium Carbonate - from what little I know, this implies mixing 100 grams with water to make up 100ml of the solution (i.e. water to make up 100ml - not 100ml of water - in fact somewhat less). I've just had another good look inside my PF box and while everything else seems to agree with the publishes formula, the PF kit contains a bag which is in fact labelled 100grams. Of course, the instructions imply mixing 75g with water to make up 100ml of solution (which doesn't agree with what I though on a 100% solution). As it turns out, I have been mixing this bag up as though it was in fact a 75g bag as detailed in the scant instructions. The long and the short of this is that I am having a dreadful time with excessive B+F with Efke 100 in Pyrocat HD on my Jobo - could this "super concentrated" Part B be the problem? Or is this 100gram bag (it weighs out at about 100 grams, so that's not a typo) the correct amount to make up a 100% solution when mixed with water to make 100ml of solution?

    Secondly, hope should I be mixing up this 100g bag to make the correct solution for B?

  2. #2

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    Quote Originally Posted by Donsta
    I've been doing a whole lot of testing with Pyrocat HD in a Jobo processor. I've just noticed, while mixing up the latest batch of chemistry (which I purchase from Photographer's Formulary) that there appears to be some discrepancy with the actual make up of the part B solution - all of the original publishing of the formaula I can source suggest that the Part B solution is now a 100% solution of Potassium Carbonate - from what little I know, this implies mixing 100 grams with water to make up 100ml of the solution (i.e. water to make up 100ml - not 100ml of water - in fact somewhat less). I've just had another good look inside my PF box and while everything else seems to agree with the publishes formula, the PF kit contains a bag which is in fact labelled 100grams. Of course, the instructions imply mixing 75g with water to make up 100ml of solution (which doesn't agree with what I though on a 100% solution). As it turns out, I have been mixing this bag up as though it was in fact a 75g bag as detailed in the scant instructions. The long and the short of this is that I am having a dreadful time with excessive B+F with Efke 100 in Pyrocat HD on my Jobo - could this "super concentrated" Part B be the problem? Or is this 100gram bag (it weighs out at about 100 grams, so that's not a typo) the correct amount to make up a 100% solution when mixed with water to make 100ml of solution?

    Secondly, hope should I be mixing up this 100g bag to make the correct solution for B?
    The original Pyrocat-HD formula called for mixing 100g of potassium carbonate with 100ml of water. When mixed that made a total of about 135ml of total solution, or about a 75% solution. That wording apparently confused some people so I changed the formula so that it now states mix 75 grams of potassium carbonate with water for a total of 100ml of solution. This also makes a 75% wpv solution.

    My understanding is that the present liquid kits distributed by Formulary have a Stock B solution that is a 75% wpv solution. I don't know about the kit that comes in powder, but you can easily weigh it yourself for verification.

    If you were to mix 100 grams with water to make a total of 100ml of solution, which is possible because of the solubility of potassium carbonate, you would have a slighter stronger Stock B than specified. It would be something like changing the 1:1:100 dilution to 1:1.25:100. That might cause a little extra general stain, but not as much as you are apparently experiencing with Efke PL 100.

    Sandy

  3. #3

    Join Date
    Jun 2004
    Shooter
    Multi Format
    Posts
    145
    Images
    2
    Thanks Sandy - I will battle on with this. I think the next step must be to send some tests off to someone with a UV densitometer to get some actual numbers...



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin