HCA - How do you know its working?

Discussion in 'B&W: Film, Paper, Chemistry' started by Martin Aislabie, Feb 13, 2009.

  1. Martin Aislabie

    Martin Aislabie Subscriber

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    Guys, I have some FB prints I would like to tone and therefore need to carefully wash.

    I have a bottle of partialy used Ilford Wash Aid that has been sitting in a cupboard for a while (no idea how long)

    I use Tetenal Protectan spray to remove oxygen for the partly used bottle.

    How do I check if the Wash Aid is still active?

    Thanks

    Martin
     
  2. analogsnob

    analogsnob Member

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    The liquid wash aids are usually some relative of ammonium lauryl sulfate (soap in simple terms) so it should last a while. I would say if the solution is clear it should work.
     
  3. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    Use a hypo-check test on the washing prints. Google for the formula - it's a few crystals of Silver Nitrate in a wee dram of dilute acetic acid.

    If you use a wash aid I think testing for residual hypo is mandatory.

    Wash aids go off, including the liquid ones, and there is no easy way to see if they are still active except by using them and finding out they aren't. I remember looking up the MSDS for the common liquid formulations and finding out they were all S. Sulfite solutions - though some of them do suds up and so they may contain detergent in addition. S. Sulfite oxidizes pretty quickly.

    If it were me, I would use a fresh wash aid. I have found Kodak Hypo Clearing agent to work better - faster washing, less hypo - than any of the liquid formulations as Orbit or Perma Wash.
     
  4. Adrian Twiss

    Adrian Twiss Member

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    Why not make your own. 200grammes of Sodium Sulphite in a litre of water which is then diluted 1:9 for use. Sodium Sulphite is dirt cheap and plentiful. I got a 5kg bucket for very little money. Just throw the working solution away at the end of each session. That way you always know it will be fresh. If using it for film add 50g of Sodium Bisulphite. According to Stephen Anchell this lowers the PH to prevent softening of the emulsion. Leaving it out improves the gloos on glossy paper.
     
  5. Ian Grant

    Ian Grant Subscriber

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    No Hypo Clearing Agents are not a type of soap, you may be confused with Wetting agents used for the final film rinse to help prevent streaking/drying marks etc. Both can be called wash aids but have totally different purposes.

    As has been said a 2% solution of Sodium Sulphite (anhyd) is fine as a HCA you don't need to add anything else and they aren't really necessary for RC papers & films. You can also use a similar strenght solution of Sodium Carbonate, which was Agfa's recommendation for their FB papers.

    Going back to Martin's original question it's possible that your HCA has deteriorated it's best used fairly fresh.

    Ian
     
  6. jim appleyard

    jim appleyard Member

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    I'd mix up new Hyop Clear. It's cheap and can save you many headaches later; like the photo turns yellow in the frame!
     
  7. dancqu

    dancqu Member

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    A Test of Sodium Sulfite as an HCA

    I've a method in mind for testing the working
    strength of a sodium sulfite HCA; a very simple
    test similar to the iodide test used on fixer. This
    subject comes up quite often. I've put off on a
    necessary series of experiments but believe
    I should now proceed. Dan
     
  8. OP
    OP
    Martin Aislabie

    Martin Aislabie Subscriber

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    Thanks Ian, that is what I thought but wanted to check.

    HCA is a leap of faith, you only realy know if it hasn't worked when it is too late

    Martin
     
  9. Chazzy

    Chazzy Member

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    This will sound like a stupid question to the chemists, but does sodium sulfite solution spoil? Isn't that the primary ingredient in these wash aids?
     
  10. Photo Engineer

    Photo Engineer Subscriber

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    Sodium Sulfite solution slowly oxidizes to Sodium Sulfate solution which is rather inactive other than decreasing the swell of gelatin and slowing any diffusion in or out of the film or paper.

    I have found over the years that wash aids are really not needed. A good wash is the best way to go with a test after the wash for hypo and silver in the coating. And, remember, you don't want to leave any type of wash aid in a coating as you risk having problems from the wash aid itself.

    PE
     
  11. Tom Kershaw

    Tom Kershaw Subscriber

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    Does this apply to Fibre Base paper generally; and could you give an indication of what problems might be encountered?

    HCA is given as standard procedure in many texts so it is enlightening to read alternative accounts.

    Tom.
     
  12. Photo Engineer

    Photo Engineer Subscriber

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    Tom;

    I have never used HCA in my entire life of doing photographs. None of my prints beyond the first few when I was about 12 years old have suffered over the 50 some years of their life.

    No problems are encountered as long as you wash well and then test to ensure that you have fixed and washed properly. Of course, this varies so much due to water supplies that you must test your own process to find the best wash condition.

    Generally, poorly washed prints have brown streaks on the back or brownish borders or spots on the front. They gradually worsen. Or, they may fade and bronze as described by Ctein in his article on this subject.

    The basic methods of washing FB papers have been outlined perfectly in articles since the 40s before the time of HCA and other chemistry was known. It is just an extra chemical to work with, buy and dispose of. And, to worry about keeping.

    If you fail to handle HCA properly and wash properly afterwards, you can see a haze on your prints, crystallization or other problems. IDK, because I avoid it. It is useless. Sistan is about the only useful post bath that has any use in this scheme of things.

    PE
     
  13. Tom Kershaw

    Tom Kershaw Subscriber

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    The use of Agfa Sistan is recommended in 'Way Beyond Monochrome' by Ralph W. Lambrecht and Chris Woodhouse; however, reading about Sistan can leave deposits on a print concerns me somewhat. When I tried to order Sistan a few months ago it was unavailable but I don't know what the situation is now.
     
  14. analogsnob

    analogsnob Member

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    Kodak Hypo clearing agent and wash aids such as Orbit are different stratigies for the same purpose.

    HCA is Sodium Sulfite with a pinch of bisulfite for buffering and to prevent excessive emulsion swelling and follows after the discovery that the thiosulfate ions washed out faster in sea water (high salt content). You then must wash the salt out of the material with fresh water or you have problems.

    Orbit and similar products work on the idea that the retention of thiosufate in the paper base is physical not chemical and they employ anionic surfactants the most common of which is ammonium lauryl sulfate which is the foaming agent in many shampoos (or in over simplification -soap).

    The wash for permanence with fb papers should be tested with the Kodak silver nitrate formula. Always when its important and atleast once to establish norms for the regimen used when ordinary work is to be done.
     
  15. Photo Engineer

    Photo Engineer Subscriber

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    I know how they work and why they work.

    Evendence exists that point to the Baryta in FB paper as being the problem because tests with plain Hot Press FB paper without Baryta shows that this paper washes faster than Baryta. But, since there are many differences such as the nature of the hot press, the pressure itself and the temperature as well as Barium Sulfate, the evidence is vague.

    I find myself that plain FB, non-Baryta paper washes faster than Baryta!

    PE
     
  16. fschifano

    fschifano Member

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    The only truly useful application I've found for HCA is for getting the magenta dyes out of TMax films. Works really fast for that, but then a proper wash does the same thing.
     
  17. Ian Grant

    Ian Grant Subscriber

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    Water is a very scarce commodity in many parts of the world, so use of a Hypo Clearing agent is a very valuable aid to significantly cutting water usage and still ensuring archival permanence of fibre based prints.

    In addition an HCA aids in promoting the solubility of some of the semi soluble silver thiosulphate intermediary complexes which can form week bonds with the cellulose fibres in a Fibre based prints. Using a two bath fixing sequence also helps.

    While good fixing procedure and a long wash works fine using a Hypo Clearing Agent is recommended by all leading paper manufactures, and has been for some years now for fibre based prints.

    Ian
     
  18. dancqu

    dancqu Member

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    And not just BS IMO. You've mentioned Agfa's suggested
    sodium carbonate HCA. Were it's use more fully tested
    and quantified it would be a better choice, it does not
    oxidize.

    My method of processing obviates any need for a Hypo
    Clearing Agent. Mine is an all alkaline method using very
    dilute chemistry one-shot. Prints wash clean with the
    minimum of water. Dan
     
  19. Ian Grant

    Ian Grant Subscriber

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    Dan, Fibre is the correct English spelling so please don't change my spellings when you quote me :D

    Agfa, Ilford Kodak etc all carried out their own research into Hypo Clearing Agents, LFA Mason of Ilford mentions a few in his book Photographic Processing Chemistry, and includes Sodium Carbonate. It should be possible to find references to the published research that Agfa carried out.

    The research I've seen indicates it's the Sodium ion that's important in helping shift the equilibrium balance of the semi-soluble silver/thiosulphate complexes towards more soluble forms. This is why a variety of sodium salts can be used like Sodium Chloride, Sodium Sulphite & Sodium Carbonate, but of course the anion may help as well.

    I would agree that your one-shot fix is a good practice, however it's far from economic, a HCA is more important when a FIBRE based prints are fixed in a more conventional manner.

    Ian
     
  20. Photo Engineer

    Photo Engineer Subscriber

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    Ian;

    No doubt that water is scarce in many areas and I totally agree with your statement in those cases. I have lived all of my life where water was, if anything, overabundant. That, colours my comments about fibre paper washing. :D

    OTOH, RC paper was invented for just that main reason and look how many people dislike it. And, how many people in these water poor areas will enjoy the cost of extra chemicals, the extra rinse afterwards, and the disposal of the chemicals? That must also be balaned in this entire equation. I'm not the one to judge this, only the person doing it and living in the area can do it. I'm just saying that any wash aid does not make or break the final quality. You do not NEED it to get good quality prints.

    PE