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  1. #1
    RalphLambrecht's Avatar
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    Self-Made HypoClear any good?

    I started to make my own HCA, mixing 20g of sodium sulfite to 1 liter (2%) as a working solution. I noticed that when I poured the solution into the tray that the last 10% or so were not as clear as the rest (the solution is a week old), but it seemed to mix OK.

    After fixing, I power-washed for 5 minutes and then used the HCA for 10 minutes, followed by a 30 minute wash. Then, I wiped the prints off (squeegee) and hung them to dry. I noticed later that the wiped-off liquid turned white. Apparently, some of the HCA is still in the print after a 30 minute wash!

    Questions:

    1. Does the residual HCA harm the print?
    2. What is the best way to deal with this?
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  2. #2
    Ole
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    3: A 2% solution of sodium sulfite should be perfectly clear, and not show any sign of sediment.

    Since yours did, there's something else in it. My first guess is that it's been mixed with "hard" water, so that you've got calcium sulfite (and sulfate) coming out of solution.

    If the wash water is also "hard", you'll have a little calcium absorbed in the emulsion which reacts with the sodium sulfite again, leading to even more white stuff! So it's not the HCA which is still in the prints, it's a trace of calcium sulfite/sulfate.

    After washing, give the prints a few minutes in deionised water. Use deionised water for mixing "HCA", or filter the solution before use.
    -- Ole Tjugen, Luddite Elitist
    Norway

  3. #3
    RalphLambrecht's Avatar
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    Ole

    Many thanks, that makes a lot of sense, because the prints brown-toned perfectly (sodium sulfite is a toner stop bath). I filtered the solution right after your post, and will use deionized water in the future. Any idea why this never happend with Kodak's or Ilford's WashAid? ... and, do you think it might harm the archival properties of the print?
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  4. #4
    David Brown's Avatar
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    Quote Originally Posted by RalphLambrecht View Post
    Ole

    Many thanks, that makes a lot of sense. I filtered the solution right after your post, and will use deionized water in the future. Any idea why this never happend with Kodak's or Ilford's WashAid?
    I could be wrong, but I have read somewhere that Kodak included in some of their formulas chemicals to deal with the impurities in domestic water. Somebody else will have to confirm this (or refute it).

  5. #5
    Ole
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    The commercial mixes all contain a sequestering agent (Calgon, EDTA or similar) for precisely this reason.

    I wouldn't expect a hint of gypsum to have any serious effects on the longevity, no. After all there's already a layer of barium sulfate in there (baryta)!
    -- Ole Tjugen, Luddite Elitist
    Norway

  6. #6

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    I think Ole is right. I had some serious print staining/cloudy solution problems when I moved my darkroom. It turned out that the water was simply too hard for the sequestering agents to do their job properly. Changing to a better water source eliminated the problems.

  7. #7
    Ian Grant's Avatar
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    Both Ilford and Agfa gave details for making your own HCA.

    Agfa recommend using Carbonate in their literature for fibre based paper processing, the Ilford bit is in Mason's Photographic Processing Chemistry, (he was head chemist a few years ago) where he recommends using Sodium Sulphite.

    The chemicals have no effect on the image at all, they help to make the residual traces of silver complexes formed during fixing more soluble, and so easier to remove.

    Most of the research was carried out during WW2 when it was discovered that salt (sea) water used to wash prints on board navy ships accelerated the washing process.

    The chemicals used in HCA / wash aids are very soluble in water so wash out extremely quickly.

    Ian

    Quote Originally Posted by RalphLambrecht View Post
    I started to make my own HCA,

    Questions:

    1. Does the residual HCA harm the print?
    2. What is the best way to deal with this?

  8. #8
    RalphLambrecht's Avatar
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    Quote Originally Posted by Ian Grant View Post
    ...
    Most of the research was carried out during WW2 when it was discovered that salt (sea) water used to wash prints on board navy ships accelerated the washing process....
    Ian
    Thanks Ian

    This is not the reason for the thread, but the actual research is much older than WW2. The WW2 story is a nice myth; the facts, you stated on the other hand, are true.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  9. #9

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    Quote Originally Posted by RalphLambrecht View Post
    Ole

    ...sodium sulfite is a toner stop bath...
    A bit of chemistry trivia. Brown toners are sulfide
    toners. Polysulfides are used. Sulfur will dissolve in
    sodium sulfide making a Polysulfide. Sulfur dissolves
    also in sodium sulfite making Thiosulfate. So, a stop
    of sulfite works because it ties up available sulfur.

    It MAY be easy to make brown toner. I've some
    sulfide solution ready. Wonder if P. Formulary carries
    sulfur. Should be interesting and maybe rewarding
    to experiment. Dan

  10. #10
    RalphLambrecht's Avatar
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    Quote Originally Posted by dancqu View Post
    ...
    Sulfur dissolves also in sodium sulfite making Thiosulfate. So, a stop
    of sulfite works because it ties up available sulfur.
    ...
    Dan

    Does that mean I'm creating fixer when trying to stop the toning?
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

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