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  1. #1
    patrickjames's Avatar
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    Sodium Hydroxide with Pyrocat..????

    I read somewhere that a 10% solution of NaOH can be substituted for the Pot. Carb. in sol. B. I was wondering if anyone uses NaOH with Pyrocat (I use Pyrocat-P) and how it affects your negatives. I am assuming that you get shorter development times and pay the price with more grain with a possibility of increased base fog (but maybe not so with the p-aminophenol).

    Anyone have any opinions or preferably experience?

    Patrick

  2. #2

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    Patrick,

    It works, and is one of the alternative variants of Pyrocat-HD that I have proposed. See here, http://unblinkingeye.com/Articles/PCat/PCat2/pcat2.html

    You are about spot on as regards results. For cons, expect slightly more pronounced grain, and a bit more B+F. There are no pros as best I could determine, except for the fact that you can buy Red Devil Lye (sodium hydroxide) at the local grocery store.

    But feel free to use either sodium or potassium hydroxide in place of the carbonates if that is what you have. It will definitely work.

    Sandy King






    Quote Originally Posted by patrickjames View Post
    I read somewhere that a 10% solution of NaOH can be substituted for the Pot. Carb. in sol. B. I was wondering if anyone uses NaOH with Pyrocat (I use Pyrocat-P) and how it affects your negatives. I am assuming that you get shorter development times and pay the price with more grain with a possibility of increased base fog (but maybe not so with the p-aminophenol).

    Anyone have any opinions or preferably experience?

    Patrick

  3. #3
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    The pH can be tempered with borax. I arrived at a solution of sodium hydroxide and borax that seems to work as well as the carbonate solution, and I think I reported it here some time ago, but I can remember neither the formula nor the date of reporting. 69 grams of borax and 14.5 grams of NaOH make a pretty close approximation to 10% sodium metaborate when enough water is added to make a liter.

    It may be that the biggest problem with pure NaOH is too much local change in pH during development. This may be exactly what is needed for compensating stand or semi-stand development of high contrast scenes.

    I would experiment with sodium metaborate. A saturated solution may offer the range of activity you want, is safer than NaOH, and is easily obtained.
    Gadget Gainer

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    Quote Originally Posted by gainer View Post
    The pH can be tempered with borax. I arrived at a solution of sodium hydroxide and borax that seems to work as well as the carbonate solution, and I think I reported it here some time ago, but I can remember neither the formula nor the date of reporting. 69 grams of borax and 14.5 grams of NaOH make a pretty close approximation to 10% sodium metaborate when enough water is added to make a liter.

    It may be that the biggest problem with pure NaOH is too much local change in pH during development. This may be exactly what is needed for compensating stand or semi-stand development of high contrast scenes.

    I would experiment with sodium metaborate. A saturated solution may offer the range of activity you want, is safer than NaOH, and is easily obtained.
    I think I read somewhere in the early days of Pyrocat when it was PMC, maybe on rec.photo.darkroom, that borax and pyrocatechol don't make a good combination. I'll try to find a reference.

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    Thanks guys! You reinforced what I was thinking. Patrick, that is an interesting thought to add the Borax. I will see if I can dig that up. My biggest hesitation is producing any base fog. I am not too worried about the grain, as long as it is sharp!

    John, that would be great if run across that information about Borax and pyrocatechol.

    The reason I am asking these questions is that I am out of developer, and need to order more to do some testing before I head out on the road for a few months.

    Patrick

  6. #6

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    I have used sodium hydroxide quite a bit. All was for negatives to contact print. At one point I had convinced myself the contact prints were sharper from the grain increase and I would not say any increased fog was a problem. I also think I may have gotten better results and smoother skies with the potassium carbonate. I stopped using the sodium hydroxide when I started using pyrocat for semistand as I worked out my dev times using potassium carbonate.

  7. #7

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    Pyrocatechol has a rather high pH development threshold, about pH 10.0 or so. If you use a 30% solution of sodium metaborate, and mix the working Pyrocat solution 1 part A + 1 part B + 100 parts water you will get a pH of about 9.2-9.6 for the working solution, as in PMK. This is too low to do much development with pyrocatechol.

    Iit is possible to mix some potassium or sodium hydroxide with the metaborate to produce a working pH over 10.0. I don't believe this would change the working characteristics of Pyrocat using the carbonates but can not say for sure since I have never done this.

    Sandy





    Quote Originally Posted by john_s View Post
    I think I read somewhere in the early days of Pyrocat when it was PMC, maybe on rec.photo.darkroom, that borax and pyrocatechol don't make a good combination. I'll try to find a reference.

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    Quote Originally Posted by sanking View Post
    Patrick,

    except for the fact that you can buy Red Devil Lye (sodium hydroxide) at the local grocery store.

    Sandy King
    Sandy, I don't think this is true anymore. I've read where sod. hydroxide is a componant of meth and was voluntarily taken off the shelves. You can no longer find it on the shelves here.

    At least there's still Artcraft, Formualry and others.

  9. #9

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    Interesting, I was not aware of that. Last time I bought it at the grocery store was three or four years ago.

    BTW, I lost a nice electronic scale with accuracy to 0.01g a couple of years ago to one of these meth heads. We had this guy doing some painting in the house, not aware of his habits, and the scales disappeared. The idiot also stole a check from my wife and forged it.

    Sandy




    Quote Originally Posted by jim appleyard View Post
    Sandy, I don't think this is true anymore. I've read where sod. hydroxide is a componant of meth and was voluntarily taken off the shelves. You can no longer find it on the shelves here.

    At least there's still Artcraft, Formualry and others.

  10. #10

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    I have also verified that Pyrocat HD part A does not work with the metaborate PMK Pyro part B,if there is no excess sodium hydroxide.Metaborate and pyrocatechol form a nearly inert complex,see the last paragraph here:
    http://www.groups.google.com/group/r...b652f0656cff82

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