Bleach question

Discussion in 'Color: Film, Paper, and Chemistry' started by Richard Harris, Aug 6, 2007.

  1. Richard Harris

    Richard Harris Member

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    Hi everybody,
    Just gone to open my bleach replenisher and found a yellow/white precipitation in the dark part, what is it and will it recombine with agitation, heat or some other means. I don't think the components are old and I put argon into the containers when I open them or, before I close them. They are Kodak Bleach replenisher in two parts A & B
    Thanks for the help, Richard.
     
  2. Photo Engineer

    Photo Engineer Subscriber

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    Richard, this white material is common in Blix solutions and indicates that the Blix has gone bad. I have never heard of it in Bleach solutions though.

    The Bleach is subject to crystals forming in the colorless part. This usually will redissolve with gentle warming.

    Even in the Blix, the white material only forms in the colorless part.

    So, this is really new to me.

    PE
     
  3. Richard Harris

    Richard Harris Member

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    Thanks R,
    sorry I'm a bit slow getting back. Yes it is the clear component of the ektacolor pro rt blix RA4. I have two batches on hand and both seem to have gone at the same time. I am interested to know two things. a, is it recoverable either by heat, agitation or addition etc? and b, what is going on chemically and how do I avoid it in future?
    Thanks again PE and anybody else who answers this thread.
    Richard.
     
  4. Photo Engineer

    Photo Engineer Subscriber

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    Richard;

    If it is the cear component of RA4, then it is the hypo going bad in that container and should be filtered before use. Also, the time should be extended due to loss of hypo.

    The best bet would be to throw it out. You can mix fresh by the following:

    ammonium hydroxide 60% - 200 ml
    sodium sulfite 10 g
    disodium EDTA 10 g

    Adjust pH to 6.7 and mix your blix as usual, one part red one part the above.

    PE
     
  5. Mike Wilde

    Mike Wilde Member

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    Typo? Ron you meant thio, not hydro right?

    Amminium Thiosulfate 60% , not hydroxide is what he meant to say.
     
  6. Photo Engineer

    Photo Engineer Subscriber

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    OMG. Mike thanks. What a goof.

    Ammonium Thiosulfate 60% - 200 ml
    Sodium Sulfite - 10 g
    Disodium EDTA - 10 g

    pH to 6.7 (use ammonia or 28% acetic acid to adjust)

    My sincere apologies to all. There was no excuse for that except being careless. GRRRR. I'm going to punish me with 10 lashes.

    PE
     
  7. Richard Harris

    Richard Harris Member

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    Thanks both,
    quick supplementary, does the ammonium thiosulphate generally come as a 60% solution and if I want to mix 2.5 ltrs of blix for my printo machine will I need to mix 6.25X the 200ml mix to make the necessary 1250ml of the clear part.
    Thanks again.
    It is so fantastic having the power of E K at the end of a qwerty keyboard.
    Richard.
     
  8. Photo Engineer

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    Richard;

    Ammonium Thiosulfate is available from several sources as 60% solution. Just use the 200 ml of this + the other ingredients added to the amount of red stuff that will make 1 liter and dilute to 1 liter. Or, you can add the water needed to the sulfite and EDTA and then add the hypo solution and red stuff. (The red stuff is Ferric Ammonium EDTA).

    The final working pH when diluted can be between 6.4 and 6.7. I prefer the high side. It keeps better at the higher pH (marginally so) but does not stop as well.

    I suggest that you use a 2% acetic acid stop to prevent processing streaks.

    PE
     
  9. Richard Harris

    Richard Harris Member

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    Thanks PE, I think I have it right now. Your mix dilutes up to 1 ltr which is the right amount to mix with part B ektacolor and dilute up to a 2.5ltrs finished solution.
    Another final question, you give a target ph value which I know Kodak gives for some of its replenishing mixes. How do you measure this? Portable meter or ph paper etc?
    Thanks again for the help R, I will search for a local supplier of chemicals, I know there is one in a town about 30mls away if not in Shrewsbury UK.
    Richard.
     
  10. Bob F.

    Bob F. Member

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    Richard, if you can't get them locally, Silverprint will have those chems for mail order.

    The ammonium thiosulphate in a 60% solution is a common way to buy it in the US but not in the UK. Normally sold as raw chemicals here. I make that 60% sol'n = 600g in water to make 1litre - or has my mental arithmetic let me down (yet again...)?

    Cheers, Bob.
     
  11. RobertP

    RobertP Subscriber

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    Hydroxide...now that would have opened his sinuses
     
  12. Richard Harris

    Richard Harris Member

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    Thanks Bob,
    I'll search their web site now.
    Richard.