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Thread: Hypo Clearing Agent and Pyro

  1. #1

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    Hypo Clearing Agent and Pyro

    Pyro users: do you use Hypo clearing agent following fixing of your film? If so, why? At what strength (e.g. 1%, 2% solution) and how long? If you don't use it, why not?

    Hypo clearing agent (Sodium sulfite in water) affects the stain of anti halation and pyro. Cole Weston used it on a number of his father's negatives (ABC pyro), Bob Herbst and Sandy King use

    it as part of their pyrogallol or -catechine processing routine. Others, for instance Steve Anchell, advise against using it.

    In responding please make clear if you refer to anti halation stain, pyro image stain, or pyro stain of film base plus fog.

    I am interested in comments based on research and/or experience.

    Thanks.

  2. #2
    IanG's Avatar
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    Re: Hypo Clearing Agent and Pyro

    You don't really need to use a hypo clearing agent with films it has little to no effect, it's really far more beneficial with fibre based papers where the intermediary semi soluable silver thiosulphate compouds formed during fixing bond weakly with the cellulose in the paper base, there are complex equilibrium equations and the sulphite tips the balance toards better soluability.

    There was a lot of mumbo jumbo about staining developers and the effects of acid fixers including the recommendation to soak the film after fixing and a short rinse in the spent developer. All the latter does is increase base staining .

    My experience with Pyrocatechin staining developers for prints (as in Ilford IT-8 toner) is the stained image is remarkably stable and not affected by Hypam/Ilford Rapid fixer or a Sulphite HCA bath. I took things to extremes with scrap test strips etc and couldn't get the stain to reduce. The Ilford IT-8 toner is a Bichromate rehalogenating bleach followed (after a good wash) by a simple Pyrocatchin re-developer, these days I use Pyrocat HD as the redeveloper because it happens to be my main film developer and this was used for my tests.

    Ian

  3. #3

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    Re: Hypo Clearing Agent and Pyro

    Very Quick Answer:

    Hans, I would base my determination/decision to use a HCA or not...
    'Solely' depending upon what Fixer -- You are presently using.

    Therefore, I personally do not use it... Only because with my TF-5 Archival Fix it is not necessary --
    And IMHO it does not affect/benefit the 'base' Pyro Image Stain.
    --
    Hans, if you have not yet read the following Thread... It too may be of some interest to you:

    http://www.largeformatphotography.in...-use-hypoclear
    --
    Thank-you. Best Regards,

    -Tim.

  4. #4

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    Re: Hypo Clearing Agent and Pyro

    I don't use Hypo Clearing Agent on any film with any developer. Since there is essentially no material present into which the thiosulfate might soak, I have never seen the need for this step. A good soaking wash with at least 5 changes of water has served me well for over 70 years. I don't have any stained or faded negatives.

  5. #5

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    Re: Hypo Clearing Agent and Pyro

    I use PMK as my standard developer. Since starting with it, I have never used a wash-aid (Hypo Clear) on the recommendation of Gordon Hutchings (who wrote the Book of Pyro). He states that the sulfite bath will remove the pyro stain. I've never tried it, so I don't know if that's true, however, I have totally removed the stain on a pyro negative when trying to selenium tone it; the stain simply disappeared. I now use bleach and redevelop to intensify stained negatives. The selenium intensification stripped the stain away and added just about enough density to replace it. Next time I have a discard neg or a test neg, I'll pop it in the Hypo Clear just to see if Hutchings was right. Maybe someone here has actually treated a PMK negative with wash-aid and has an answer?

    As for anti-halation dyes: these almost always come off in the pre-soak or the development stage. The pink cast many negatives have is due to stubborn sensitizing dyes. I find an extended fix (I use Hypam or Rapid Fixer) removes the stain on the films I use (Kodak 320 Tri-X and TMY) with no need for a hypo-clearing bath. Fixing film a bit longer has no ill effects.

    FWIW, as many have said, a wash-aid is not really needed for film. However, if you check out the sticky thread on film washing at APUG http://www.apug.org/forum/index.php?...ng-test.69416/ you will see that a wash-aid does speed things up a bit. Just make sure you are washing long enough. I wash for minimum 30 minutes.

    Best,

    Doremus

  6. #6
    IanG's Avatar
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    Re: Hypo Clearing Agent and Pyro

    That's interesting Doremus, maybe the Pyrogallol stain is less stable than Pyrocatechin stain.

    Ian

  7. #7

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    Re: Hypo Clearing Agent and Pyro

    Sodium Sulfite removes stain.

    You can use it to clean grape juice or wine stains. It is a bleaching agent: see http://www.chemistryexplained.com/Ar-Bo/Bleaches.html

    When using Pyrocat you can use it as a Hypo Clearning Agent (if needed) and you can use it to remove the magenta sensitizing dye of films like Kodak TMax if your fixer isn't fresh enough to remove it entirely. The danger is that you start to remove the pyro stain if you over-do it.

    1 teaspoon per liter for 5-10 minutes at 20 deg C is a good mix.

  8. #8

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    Re: Hypo Clearing Agent and Pyro

    Quote Originally Posted by Ken Lee View Post
    Sodium Sulfite removes stain.

    You can use it to clean grape juice or wine stains. It is a bleaching agent: see http://www.chemistryexplained.com/Ar-Bo/Bleaches.html

    When using Pyrocat you can use it as a Hypo Clearning Agent (if needed) and you can use it to remove the magenta sensitizing dye of films like Kodak TMax if your fixer isn't fresh enough to remove it entirely. The danger is that you start to remove the pyro stain if you over-do it.

    1 teaspoon per liter for 5-10 minutes at 20 deg C is a good mix.
    I don't use HCA, and as far as the pink cast, life's way too short to use tired fixer. What's another 50 cents to ensure several bucks worth of film, and priceless time to make negatives?

    Just my 2 cents on top of the 50.
    Bruce Barlow
    author of "Finely Focused" and "Exercises in Photographic Composition"
    www.brucewbarlow.com

  9. #9

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    Re: Hypo Clearing Agent and Pyro

    I've been using Heico Permawash since the dawn of time and have used it for PMK negs and they still have that wonderful greenish-yellow hue. I know it's really not necessary with film but old habits yano
    notch codes ? I only use one film...

  10. #10

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    Re: Hypo Clearing Agent and Pyro

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    Thank you all for your input.
    My concern is that I might cause deterioration of the pyro image stain when diminishing or removing base+fog stain. Some in the pyro community use HCA routinely while others advise against it's use. That's why I started this thread, just curious.
    I shouldn't have mentioned the anti halation stain, as Doremus explains it usually disappears during the presoak. I meant the bluish sensitizing dye.
    As far as the use of HCA and non-pyro film developer- I don't use it after fixing. My negs from the 50's, 60's are still fine. Washed in tap water 20C, 15 minutes.
    My solutions are always fresh. I buy sod. sulfite in 50 lbs bags, minimum purchase 2 bags- same for hypo. So feel free to contact me if your supplies are low.......

    Ken 1 tsp HCA per liter seems a bit low, I wonder if you mean 1 tablespoon.

    Thanks again.

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