prehardening questions

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by narigas2006, Feb 11, 2007.

  1. narigas2006

    narigas2006 Member

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    Hi all,

    Thanks for all the help with my coating film problems... Hologram's suggestion of KOH prebath of the film base (i said acetate first but it's polyester) worked fantastically with normal gelatin. It really sticked! I gave up hardening before shooting as the emulsion gets too hard, but do you think a pre hardening before developing is a good idea? I was thinking something like a 1% formaline solution. What do you think? Many thanks!
     
  2. Photo Engineer

    Photo Engineer Subscriber

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    Here is the formula for a good prehardener.

    Water 500 ml
    formalin 37% 10 ml
    Sodium sulfate 100 g
    water to 1 L

    pH ~9.5

    Use for 1 - 2 mins at 68 degrees.

    I'm glad to hear that the KOH treatment worked for you. I've never heard of it. Live and learn.

    PE