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  1. #11

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    Quote Originally Posted by jbrodkey

    However Sandy says you should mix the stock solutions under a hood or outside.
    I live in an apartment house - no hood and hard to work outside. Photographer's Formulary
    only supplies the powder although they do provide the stock solutions for several other Pyro developers. Why don't they supply Pyrocat in liquid form. Is there some reason for only supplying the powder?
    First, thank you for your nice comments about the article.

    I can't speak to Formulary's marketing practices since I have no involvement with their distribution of Pyrocat-HD.

    As to the other issue, the recommendation to mix the chemicals outside or with a vent hood is made to err on the side of safety. I personally mix indoors with a filtered mask of the type available at hardware store, taking care to keep the chemicals being mixed downwind of any air currents that may be present, and would not hesitate to recommend this procedure for any reasonably prudent and careful person.

  2. #12

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    What a great article. It's time for me to mix some up and try it. One part of the mixing instructions I was not sure of, mixing part B. When you say that the "The total amount of solution will be slightly in excess of 1300ml" does that mean that the instructions for part B actually make 1300mL?

    In other words, if I want to make 1000mL of part B should I use 769g of potassium carbonate?

    Most formulas end with "water to make 1000mL"

    I've avoided trying Pyrocat-HD because I thought it might be a little grainy for my small negatives, but I'll give it a try.

  3. #13
    Ole
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    I mix mine indoors, in the darkroom. No hood or anything, either.

    The two most dangerous ingredients are the Pyrocatechin itself, and the Potassium Carbonate.

    The basic safety precaution is to keep fingers and nose well clear of chemicals; weigh carefully; and mix quickly.

    Avoid blowing (includes sighing, sneezing and even gentle exhalation) into dry chemicals to avoid spreading them about. In the same way, don't inhale them. If you can smell the Pyrocatechin, you're a little close. A mask is a good idea, but it may lure you into getting too close.

    I would not mix chemicals outdoors if there's even the slightest chance of a breath of wind for the same reasons: I like dry powder to stay put.
    -- Ole Tjugen, Luddite Elitist
    Norway

  4. #14

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    [quote="john_s"]What a great article. It's time for me to mix some up and try it. One part of the mixing instructions I was not sure of, mixing part B. When you say that the "The total amount of solution will be slightly in excess of 1300ml" does that mean that the instructions for part B actually make 1300mL?

    In other words, if I want to make 1000mL of part B should I use 769g of potassium carbonate?

    Most formulas end with "water to make 1000mL"

    Thank you for alerting me to this matter.

    This part of the article is confusing and will I will see that it is changed as soon as possible. With the Stock Solution of Pyrocat-HD we should start with 1000ml of water and slowly add to the water 1000g of potassium carbonate. This will make a total amount of Stock B solution of approximately 1300ml. Previously published formulas made this step clearer but I can see that there could be some confusion with the directions as provided in the article.

  5. #15
    Ole
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    Sandy,

    Think you could change the recipe to give 1000ml final solution? It would be a lot easier for those of us who put the finished solutions in 1000ml (or 100ml, in my case) bottles.

    Since I have a very good little electronic balance, I make 100ml at a time. A whole liter would give 100 liter finished developer at 1:1:100, which would be more than I can use. 100ml is generally used in a couple of months; well within the lifetime of the solutions. My first batch lasted me six months, with no sign of deterioration. BTW, I use Nalgene bottles...
    -- Ole Tjugen, Luddite Elitist
    Norway

  6. #16

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    Ole says above"Think you could change the recipe to give 1000ml final solution? It would be a lot easier for those of us who put the finished solutions in 1000ml (or 100ml, in my case) bottles. "

    That's what I was driving at when I suggested 769g with water to make 1000mL, based on Sandy's figure of 1kg pot carbonate plus 1Litre water to make "approximately" 1.3Liter. If it's hard to get all of the pot carbonate to dissolve (sounds like a possibility) i'd be tempted to make up half strength part B and use 2x as much (as I do with PMK, since I found it impossible to get the full amount of metaborate to dissolve in the required amount of water)

  7. #17
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    vvg article-excellent intro but covers plenty of ground as well. You mention using hypo clear btw-won't the sulfite in this remove some of the stain?
    "He took to writing poetry and visiting the elves: and though many shook their heads and touched their foreheads and said 'Poor old Baggins!' and though few believed any of his tales, he remained very happy till the end of his days, and those were extraordinarily long "- JRR Tolkien, ' The Hobbit '.

  8. #18
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    I can address the enlargability issue. I use pyrocat with 35mm film, and the grain is about the same as the tried and true d-76 1:1. It is noticeably sharper because it doesn't have all the sulfite that D-76 has in it. I find it to be a perfect roll film all purpose do-anything developer, without the fussiness of the other pyro formulations.

    Clay

  9. #19

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    Jdef,
    I can address several of your questions based upon my personal experience with both developers. I have used ABC before I switched to Pyrocat. The matter of staining and VC paper is not so much a matter of stain as it is the color of the stain.

    In pyrocat the brown stain color does not have the effect of reducing high print value contrast to the extent that ABC does (due to the brown versus greenish stain). Green is the light color that gives a reduction in contrast with VC papers whereas blue serves to increase contrast. I noticed a marked difference with the first Pyrocat developed negatives that I enlarged on VC paper. Additionally I have found that Pyrocat does not suffer from the uneven development that I experience with some of my ABC negatives.

    I have found that in several films that there is an increase in effective film speed. Bergger BPF 200 for instance benefits by 1/3 stop over ABC.

    I would concur with Clay that Pyrocat is a good developer for a variety of applications. The only area where ABC may have a slight advantage to Pyrocat is possibly in shadow tonal separation. I believe that Sandy King addressed that on the Azo Forum sometime ago. Pyrocat does offer better highlight tonal separation then ABC however.

  10. #20

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    Jdef,
    No the benefit of a staining developer is that it is proportional to silver density so that the stain effect is greatest in the areas of greatest silver density. Therefore a staining developer will serve not only to increase overall negative contrast but also to increase local contrast in the areas of higher negative density (print highlight areas).

    In the case of a staining developer that imparts a greenish stain (ABC and PMK) with VC materials the effects are counter to the desired result. We are increasing contrast with the stain effect but then we are decreasing contrast through the color of the stain. This occurs by the fact that the stain color acts as a variable contrast filtration factor in it's own right.

    To decrease print highlight contrast would tend to lump the highlight values into a blocked condition at it's extreme condition. To increase highlight contrast is to separate highlight values into more definable values. I hope that I have expressed this clearly.

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