storage of finished emulsion

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by rmazzullo, Apr 6, 2007.

  1. rmazzullo

    rmazzullo Member

    Messages:
    263
    Joined:
    Mar 24, 2007
    Shooter:
    Medium Format
    Hello PE,

    Is there a "shelf life" to a batch of finished emulsion? What would be the best way of storing a batch of finished emulsion for later use without damaging it?

    Thanks,

    Bob Mazzullo
     
  2. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,773
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    If the emulsion is not stabilzed with Thymol to prevent the growth of bacteria and mold, then its life is very short indeed.

    If stabilzed, it will last quite a while. I have had the raw emulsions that I make last at least 6 months in a refrigerator.

    But, a 'finished' emulsion implies to me that you have added sulfur or sufur + gold senstitzation. We usually sensitized emulsions this way prior to use, and added stabilzers as the raw emulsion keeping goes down after sulfur or sulfur + gold addition.

    See my previous posts on this process.

    PE
     
  3. hrst

    hrst Member

    Messages:
    1,300
    Joined:
    May 10, 2007
    Location:
    Finland
    Shooter:
    Multi Format
    Browsing around some old posts to rehearse all this information...

    Indeed, the emulsions don't keep too well without thymol.

    However, I would like to ask if I can stabilize the emulsion with thymol just after the noodle wash, that is, BEFORE the finishing steps---does it affect the sulfur(+gold) sensitization step? Or should I make the sulfur sensitization first and then add thymol as the last addition before storing for coating?
     
    Last edited by a moderator: Sep 5, 2010
  4. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,773
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    You can store both before and after the sulfur or sulfur + gold sensitization steps. We did both at EK depending on time of day and schedule. I have now kept an emulsion with thymol for 1 year. It will vary from emulsion to emulsion.

    PE
     
  5. hrst

    hrst Member

    Messages:
    1,300
    Joined:
    May 10, 2007
    Location:
    Finland
    Shooter:
    Multi Format
    Thank you again for your help!
     
  6. alexhill

    alexhill Member

    Messages:
    177
    Joined:
    May 22, 2010
    Location:
    New Hampshir
    Shooter:
    4x5 Format
    Once again, awesome stuff. I've got a batch that has been sitting in a fridge for 2 months that was treated with Thymol.
     
  7. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,773
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    I now have a sample of a better preservative (actually two of them) that might help. Unfortunately, it was preserved with copper which hurts emulsions.

    PE