Pyrocat-HD

Discussion in 'B&W: Film, Paper, Chemistry' started by Jimbob, Feb 4, 2004.

  1. Jimbob

    Jimbob Subscriber

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    I having trouble mixing the "B" solution. I keep ending up with what appears to be an unmixed solution. I talked with the Photographers Formulary and was given advice about mixing the Potassium Carbonate to quickly. So I tried another batch mixing it much slower. However, I ended up with a milky looking stock solution. When it sits for a while it separates. I've tried mixing at both 68 degrees and 100 degrees. Same result. Can anyone help?

    Thanks
    JIMBOB
     
  2. juan

    juan Subscriber

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    Sometimes it's hard to mix. Are you using distilled water - that may help. I use sodium carbonate, and it's even harder to mix with water. I mix it in 5 times the amount of water, then, when mixing the working solution, add five times as much. That gets the right amount of chemical into the solution, and the added water is not enough to worry about.

    With potassium carbonate, you might want to try doubling the amount of water for the stock solution. Then, if you are using the working solution 1:1:100, you'd actually use 1:2:100.
    juan
     
  3. Tom Duffy

    Tom Duffy Member

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    you can still use the solution if you stir it up before adding to the water for the working solution. going forward, you should addthe potassium carbonate VERY slowly into the 100ml of water, taking care to disolve it a little bit at a time.
     
  4. L Gebhardt

    L Gebhardt Subscriber

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    I had the same problem. I beleive the dirrections say to add it to 100ml of water, not add water to make 100ml. I think I added about 30ml more water and it desolved. I am still confused by the directions, and I think I will mix it from scratch next time.
     
  5. gainer

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    You should try using triethanolamine in place of the Kodalk or metaborate solution. Triethanolamine (TEA) is available from Photographer's Formulary or www.chemistrystore.com. Use the same amount of it as you do PMK A solution. That is, for example, 10 ml A + 10 ml TEA + 1000 ml water.

    This avoids all the hassle of mixing metaborate and the uncertainty of exactly what Kodalk is. TEA is an organic base that becomes basic when you add it to water.
     
  6. gainer

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    Whoops! I am getting too old. What I said about TEA applies to PMK. TEA may not be alkaline enough for Pyrocat-HD.

    The cloudy carbonate solution may be due to hard water, which contains calcium and/or magnesium. Their carbonates are insoluble and form the cloudy solution you described. Tetrasodium EDTA may cure it, but it's cheaper just to use distilled or demineralized water unless you have on hand the EDTA.
     
  7. sanking

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    Quite a number of folks have reported difficulty in mixing the B solution of Pyrocat-HD with the Formulary kit. Since I have never used this kit I don't actually know either exactly what is in there, nor the directions for mixing. Perhaps if you could send me a description of how the kit is packaged, and the directions for mixing, I could figure out the problem.

    I have always mixed Pyrocat-HD from bulk chemicals and not from a kit, and when the potassium carbonate is added slowly to the water, as described in the article at www.unblinkingeye.com, I have never had a problem with getting the chemical into solution. And there should not be either, since potassium carbonate is soluble in water in percent solutions well over 120%, and one is nowhere near this figure when adding 100g of chemical to 100ml of water.

    One of the mistakes that a number of people have made in the past is to attempt to mix the 100g of chemical in water to make 100ml of solution, but as someone points out further in this thread, the correct way to mix is to add 100g of chemical *slowly*, and with constant stirring, to 100ml of water, which will give a final total solution of around 125-35ml of B stock solution. Since slowly is a relative term I will qualify it for this context by saying that it should take no longer than about two minutes add the potassium carbonate to the water and have it completely in solution. And contrary to some recommendations I have seen, water at room temperature (70F or greater) has always worked fine for me.
     
  8. gainer

    gainer Subscriber

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    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.
     
  9. Jimbob

    Jimbob Subscriber

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    Success! Thanks to all for your help. One thing I really appreciate about photographers is there willingness to share information.

    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. I've experienced few problems with mixing chemicals. The kit may the culprit.

    Anyway, thanks again!
    Regards,

    Jimbob
     
  10. roy

    roy Subscriber

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  11. john_s

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    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
     
  12. sanking

    sanking Restricted Access

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    Hi Gadget,

    Damn, another Gainer!!

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

    Sandy
     
  13. Leon

    Leon Member

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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
     
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  15. juan

    juan Subscriber

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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
     
  16. gainer

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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.
     
  17. roy

    roy Subscriber

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  18. john_s

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    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.
     
  19. sanking

    sanking Restricted Access

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  20. Leon

    Leon Member

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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
     
  21. roy

    roy Subscriber

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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.
     
  22. sanking

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  23. Leon

    Leon Member

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    thanks sandy. Over exposure is highly probable - i really dont think that that Holga was the best camera for a trial run!!!

    I have posted an image from a neg scan in the technical gallery - the grain is much less prominent than I expected it to be after looking at it on the light box - trouble is, I cant print it properly at the moment as I dont have my dark room done .... wont be long though.
     
  24. Jim Chinn

    Jim Chinn Member

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    My Holgas always seem to give some overexposure on very sunny days. The PyrocatHD in my experience allows you to shoot at the regular film rating so you probably were over by one stop. And of course those wonderfull holga optics are going to provide a pretty contrasty neg anyway with sunlight.

    Right now HP5 and PyrocatHD are my choice for my LF work.
     
  25. sanking

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    BTW, am I looking at distortioin in the horizontal lines (from the Holga lens) or does the top of the building really have that shape?

    Sandy
     
  26. Leon

    Leon Member

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    that'll be the holga Sandy.