foma emulsion / bromoil

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by claudius, Dec 28, 2013.

  1. claudius

    claudius Subscriber

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    hi everybody,
    (Emil Gandolfi in particular)
    making bromil.
    I bought Foma emulsion in 1 kg bottle, coatet 5-6 watercolor papers.
    so far no problems.
    two weeks later the emulsion has stiffened in the black bottle, need a spoon to get it out.
    no hardener added, kept airtight and dark in 18 degre C.
    after heating the stiffened stuff up to 40 degree C it is liquid as normally.

    emulsion expires april 2014.
    i have not yet developed any, will it work ?


    have you seen this before?
    is it a bad batch ?
    will diluting with water be any good ?
    i am a bit worried as i bought 2x1 kg, now kept in refrigerator.



    klaus
    denmark
     
  2. gandolfi

    gandolfi Member

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    not quite sure what you mean, but the emulsion is supposed to be stiff in the bottle. It liquifies when heated.

    So it sounds normal - not a bad batch - no water should be added.

    Kept in the frigde it can last a long time...
     
  3. claudius

    claudius Subscriber

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    pyu, thought the emulsion was bad.
    on the other hand, when i opened the bottle first time, it was liquid, precisely as i recall it from the seminar on Vraa Hojskole last summer, also out of the fridge.
    thanks Emil.
     
  4. gandolfi

    gandolfi Member

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    if it was liquid when you took it from the frigde, then there's only one reason: somebody had just used it - heated to liquid state and then after use, put it back - you took it before it set again....
     
  5. Photo Engineer

    Photo Engineer Subscriber

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    Continued reheating the entire batch will cause changes to take place and will gradually lead to it going bad (foggy probably). Small amounts should be removed for use before melting, by using a spatula or spoon. This is why emulsion should be kept in wide mouth bottles, jars or cans (light tight of course).

    PE
     
  6. claudius

    claudius Subscriber

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    thanks both of you.
    a spoon is ready in the darkrom as from now.
    once heatet, i presume its ok to pour remans back in its container.
    klaus
     
  7. cliveh

    cliveh Subscriber

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    I don't understand this thread, as my experience with bromoil exhibits no stiffness in the bottle or otherwise. What is this about?
     
  8. andreios

    andreios Member

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    It's about solid state of liquid emulsion before actually using it, e.g. in the bottle. :smile:
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    If you heat and melt some emulsion (say 40C or higher) do not save it in the bottle with the main bulk of your emulsion. If you must save it, save it in another container. Heating emulsion until it melts changes it.

    Having liquified emulsion is abnormal. It should be stored in a refrigerator, and when you do that, the gelatin should become stiff. I cut mine with a knife and dish the solid out with a spoon. At work, we used such large amounts that we used rubber gloves to grab a big chunk and then we weighed out what we needed. We had space in a walk in cold store for the huge mass of emulsion, stored in 10L or larger cans.

    PE
     
  10. cliveh

    cliveh Subscriber

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    Oh I see, I have always made bromoils with paper that has an emulsion.
     
  11. gandolfi

    gandolfi Member

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    SO yester year... :wink: