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  1. #1
    Willie Jan's Avatar
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    Pyrocat HD as paper developer?

    Just wondering,

    does anyone use pyrocat HD as paper developer?

  2. #2
    Ian Grant's Avatar
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    One major problem with any Pyrocatechin developer is oxidation, this shows increased base stain/fog which isn't a problem with negatives but degrades the highlights with prints.

    In a print tray the Pyrocatechin will suffer from oxidation far faster than in a developing tank, so the developer has a very short life and needs to be changed every 2 or 3 prints.

    Have a look at Ilford IT-8 toner. It uses a dichromate bleach followed by a Pyrocatechin re-developer. Wonderful olive black tones.

    IT-8 Ilford Pyrocatechin Toner
    For Olive Black tomes.

    Stock A
    Potassium Bichromate 50gms
    Water to 1 litre

    Stock B
    Hydrochloric Acid (conc) 100ml
    Water to 1 litre
    Expose and process your print as normal and wash well.
    Make up bleach from: 2 parts A and 10 parts B with 40 parts water, bleach the print then wash until all the yellow from the bichromate has been removed from the highlights then redevelop in the following Developer.

    Developer
    Pyrocatechin 1.75gms
    Sodium Carbonate (anhyd) 5gms
    Water to 1 litre

    Temperature is not critical, it should take 1½ to 2 mins at 20°C, this developer will oxide very quickly and should be discarded when it turns a bluish green.

    Ian

  3. #3

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    This is not exactly what you're looking for, but related:

    http://unblinkingeye.com/Articles/Py.../pyroplus.html

  4. #4
    Willie Jan's Avatar
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    Why i am asking this is that i am searching if it is possible to get more details in the highlights(clouds) with a different developer. Standard i use am6006 amaloco, a friend tried eukobrom and found out that after 5 minutes there is still coming more detail in the highlights where my default developer stops working.

    (Eukobrom is not for sale where i live..)

    That is where i started to ask myself it a pyro developer would give better results...
    But i forgot the oxidation..

  5. #5

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    Quote Originally Posted by Ian Grant View Post
    In a print tray the Pyrocatechin will suffer from
    oxidation far faster than in a developing tank, so
    the developer has a very short life and needs to
    be changed every 2 or 3 prints. Ian
    Perhaps it would be amenable to use as a very dilute
    one-shot with somewhat extended development. Dan

  6. #6
    gainer's Avatar
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    The Pyrocat developers all have the necessary ingredients to develop paper. When used on film as Sandy King proposed, they are highly diluted, high pH , low sulfite solutions. If you consider what you might do to make, say, Dektol usable on film, you could dilute it or lower its pH or both. The other way round, then, you could increase the concentration of the A solution, add some sulfite to the working solution, and see what happens.
    Pyrocatechin and hydroquinone are like twins with different-colored hair. It is not pyrocatechin that uniquely makes Pyrocat a tanning, staining developer. Hydroquinone would do so as well, but with a different color of stain. The stain color of pyrocatechin is particularly desirable for negatives intended for printing by certain "alternative" methods. Sulfite is the great stain remover in pyrogallol or pyrocatecchin developers, so little is used. In fact, the Pyrocat series in glycol have none.
    Now if the stain is the prize to be gained, the short developer life is the penalty. Otherwise, I don't see how the use of pyrocatechin will benefit. Pyrogallol can stand considerably more sulfite and still produce some stain, but most of us don't want our hands in pyro developers.
    Gadget Gainer

  7. #7

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    A note on the Ilford developer recipe given above: Good laboratory practice requires adding concentrated acid to water, not water to acid. It would be better to add the acid to 750 ml water then top it up to the required amount with more water. Water added to concentrated acid can flash to a boil and spatter the acid.

    Peter Gomena

  8. #8
    gainer's Avatar
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    Concentrated HCl is in the neighborhood of 30% IIRC. The general rule is a good one, even so.
    Gadget Gainer



 

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