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Thread: Pyrocat-HD

  1. #11

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    Quote Originally Posted by Jimbob
    I found by adding the Potassium Carbonate to 200 ml of distilled water it cleared up almost immediately. I'll just work with the 1:2:100 dilution.
    Jimbob
    It seems to me that adding another 100mL water does not give "half-strength" Part_B.

    When you add 100mL water to 100g potassium carbonate, you get about 130mL according to Sandy's instructions (The Great 21st Century Book of Pyro). So there is

    100g potassium carbonate per 130mL of solution = 77g per 100mL of solution (approx)

    If you add 100mL water to the 130mL which you were trying to make in the first place, you have 100g in 230mL of solution which is 43.5g per 100mL. Using 2 times the amount of this Part_B is equivalent to using a Part_B of 2x43.5=87g/100mL instead of 77g/100mL. Maybe 13% more pot.carbonate won't make much difference, but you might as well avoid the variable. You can correct it by instead of adding 100mL water, just add enough water to double the volume (130mL in this case)

    (And to be really pedantic, you could mix it 1+2+99 to account for the extra water in your new Part_B.)

    (Sandy's mixing instructions have caused some confusion. I think I even saw a Formulary pdf that said erroneously "add water to 100mL". Maybe it's been corrected since then.)

    Is my reasoning correct?

    Incidentally, here we have town water of low mineral content and I had no trouble making standard Part_B

  2. #12

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    Quote Originally Posted by gainer
    I mixed 350 grams of Potassium carbonate with 350 ml water to get 500 ml of solution with no problem, but I have hard well water, so I used either rain water or distlled water from the store, I don't remember which. When I dissolve any carbonate in my well water, I get the cloudy solution which eventually precipitates the calcium-magnesium carbonate.
    Hi Gadget,

    Damn, another Gainer!!

    You would not be related to that infamous Vitamin C experimenter Patricik Gainer, now would you?

    Sandy

  3. #13
    Leon's Avatar
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    I have just mixed up my first brew of pyrocat-HD. I had enough potassium carbonate to mix with 150 ml distilled water for the b solution. I too found that it would not dissolve ... i followed the advice from this thread and mixed it VERY slowly in very small amounts at a time, with de-ionised water and at 20 deg. The first few amounts dissolved perfectly but after about the 4th or 5th it became very thick and powdery. and i still had about 1/2 of the powder to put in!. In the end I doubled the amount of water and it all dissolved in less than a minute!

    Now I'm ready to start testing - can anyone give me any approximate starter times and ei's for 120 pan f, delta 100 and HP5+ in tanks?

    TIA

  4. #14
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    john_s, I'm no chemist, but I don't think you're quite right. I'm saying add the carbonate to 200ml of water, not add 100ml of water to the 130ml containing the carbonate. By my way of thinking, that means double the solution contains the same amount of carbonate.

    Perhaps changing the water to 99 parts would be more useful, but as a practical matter, I haven't seen the need to do this. But then I develop by inspection, so any slight change is compensated for in my procedure.

    Over at michaelandpaula.com, there are a couple of threads on using Pyrocat HD with various minimum agitation plans. There, the use 1:1:150 to 1:1:175, so I dont' think the volume of water is critical - just something that needs to be accounted for in one's regular procedure.
    juan

  5. #15
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    Sandy,
    I am the same. Funny you should have spelled my name that way. My mother was born in Poland. There are lots of Gainers in West Virginia. Every reasonably large city I have visited had some in its phone book.

    I got the nickname when I went to work at NACA, now NASA. In those days, the reproduction was done by Ozalid, a photo process developed in ammonia fumes. Some of my coworkers had spent a lot of unpaid overtime reproducing long rolls of flight records from 70 mm film oscillograms to ozalid. They got to the office next morning and found that the ozalid developing machine had not worked. I could see faint yellow traces on the paper, and I knew about the ammonia developer. I found some household ammonia in a janitors closet, put an open container in my large desk drawer with a loosely rolled spool of undeveloped paper, and after a while the traces popped right up. They were happy. Soon, every large desk drawer in the office was an ozalid developer, everyone's sinuses were cleared for days, and I got my nickname.
    Gadget Gainer

  6. #16
    roy
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    [quote="Leon"]Now I'm ready to start testing - can anyone give me any approximate starter times and ei's for 120 pan f, delta 100 and HP5+ in tanks?

    Keep us posted on your experiences Leon, I shall be using this soup in the near future.
    Roy Groombridge.

    Cogito, ergo sum.
    (Descartes)

  7. #17

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    Quote Originally Posted by juan
    john_s, I'm no chemist, but I don't think you're quite right. I'm saying add the carbonate to 200ml of water, not add 100ml of water to the 130ml containing the carbonate. By my way of thinking, that means double the solution contains the same amount of carbonate.
    juan
    If you add the carbonate to twice the specified amount of water, you don't have twice the volume of solution. And consequently, you don't have exactly half-strength Part_B.

    How much does this matter? As you say, if one is consistent, there is unlikely to be a problem. In fact, you might have found a slightly better formula than Sandy! At least for your chosen film. I don't know. I was just talking about the mixing concentration.

  8. #18

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    [quote="john_s"]

    (Sandy's mixing instructions have caused some confusion. I think I even saw a Formulary pdf that said erroneously "add water to 100mL". Maybe it's been corrected since then.)


    Just for the record, I don't have a thing to do with the Formulary kit so don't blame me for whatever mistakes they may have made in packaging or in the instructions. If they were paying me for the use of the formula I might feel some obligation to make sure they have it right, but as things stand that is their responsibility .

    In any event doubling the amount of water and mixing the working solution 1:2:100 (or 2:4:100) should work fine, but you may need to adjust develoment times down slightly because mixing this way will result in slightly more carbonate per liter of working solution, making the developer a tad bit more energetic, or fast working.


    Sandy

  9. #19
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    I have dev'd my 1st film in pyrocat hd. It was a mix as prepared by Michael Maunders at speedibrews (extremely helpful - well recommended).

    Now, admittedly it was with a roll of hp5 put through my holga (wiht no way of knowing exposure etc) - but i was like a kiddie with a new toy and was desperate to try out the developer. I used it at 1:2:100 (as I had difficulty in dissolving the second solution, I made it up to 300ml with distilled water instead of the 150ml of solution i was trying to make - so this is really the approximate equivalent of 1:1:100) at 21 degrees and used the partial stand - 2 mins initial agitation, then 10 seconds every 3 mins for a total of 22 mins 30 secs

    So - initial reactions - the negs are very dense, the stain is extremely brown and prominent, (as compared to mild and weak with exactol lux) they are bitingly sharp (even when taken with the holga!). There is very good shadow and highlights details. I have only scanned the negs so far, but have found the grain to be really heavy (sharp but heavy). The tonality is wonderful though.

    Is this what common users would expect with Pyrocat-HD and this film? I think i could shave some time off in the hope that they woudlnt be quite so dense - or perhaps reducing some of the b bath would do the trick, although this would also reduce contrast - right?

    It probably wasnt the best of ideas to start with a holga film, but I am planning to do some comparison tests with my "proper" mf camera very soon with hp5, delta 100 and pan f.

    any thoughts / suggestions on the above would be greatfully received as i have seen some of your amazing results with this stuff, and could do with some guidance

  10. #20
    roy
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    I have nothing to add as I am keeping a watching brief, Leon. It does seem however, that you are satisfied apart from the density. At least you have something to work on now, to improve and get the results you want. Well done.
    Roy Groombridge.

    Cogito, ergo sum.
    (Descartes)

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