splitting tetenal 1L c41 press kit?

Discussion in 'Color: Film, Paper, and Chemistry' started by BenJT, Jan 29, 2013.

  1. BenJT

    BenJT Member

    Messages:
    37
    Joined:
    Dec 11, 2012
    Location:
    Boston MA
    Shooter:
    Multi Format
    Hi, pretty simple question and I'm sure I could find the answer but figured I'd just as. I just bought this powder kit to develop some 120 film in my Paterson tank. The tank I use is the one that does 2 rolls of 135 or 1 roll of 120. When doing BW I mix up 500ml (50:1 rodinal) solution, I'm thinking since this is the one liter kit I can effectively mix 500ml now, use it till its exhausted, and then mix the remaining solution for another 500ml. I am assuming I should get more rolls out of the kit doing this? Is it worth it or should I just mix it all at once?
     
  2. MattKing

    MattKing Subscriber

    Messages:
    17,035
    Joined:
    Apr 24, 2005
    Location:
    Delta, BC, Canada
    Shooter:
    Multi Format
    Don't mix up parts of powder kits - there is no way to ensure they are homogenous.
     
  3. BenJT

    BenJT Member

    Messages:
    37
    Joined:
    Dec 11, 2012
    Location:
    Boston MA
    Shooter:
    Multi Format
    I wasn't planning on it, Im already paranoid enough about F'n this up.
     
  4. Rudeofus

    Rudeofus Subscriber

    Messages:
    2,586
    Joined:
    Aug 13, 2009
    Shooter:
    Medium Format
    One thing you could do is mix the whole liter, use 500ml for your immediate processing and put the other 500ml into some air tight bottles which you store in some cool place. This way you should be able to use the second 500ml batch a few months later without problems.
     
  5. chuck94022

    chuck94022 Subscriber

    Messages:
    684
    Joined:
    Jan 11, 2005
    Location:
    Los Altos, C
    Shooter:
    Multi Format
    The working solution will degrade much more quickly than the liquid stock variations of tetenal you can buy. This is because the water at working solution dilution contains plenty of oxygen to help the chems begin the process of self immolation. I question whether you can get to "several months", but if stored well (glass with no air in contact with the surface of the fluid) it should last at least six weeks. My working solution is older than that, and being used, and is still alive, so I do know there is some cushion built into tetenal's estimated life expectancy of working solution. (My kit says 6 weeks for working solution.)

    That said, I'd caution you to do a test before developing something critical with chems that are past their expected shelf life, and brew some new soup if the tests show degraded performance.
     
  6. michael stevens

    michael stevens Member

    Messages:
    38
    Joined:
    Feb 16, 2010
    Location:
    England
    Shooter:
    35mm RF
    Maybe you could try freezing or chilling the second 500ml to increase its shelf life.
     
  7. Rudeofus

    Rudeofus Subscriber

    Messages:
    2,586
    Joined:
    Aug 13, 2009
    Shooter:
    Medium Format
    I wholeheartedly agree that storing a concentrate will be better than storing a working solution, but that appears to be not an option here. Splitting a powder mix is generally not recommended and making a concentrate from it may or may not work. What I suggested was the best he could do with the kit he got.

    Since Tetenal's C41 working solutions are known to last very well I am quite confident that a tightly sealed bottle of working solution can be stored for many months. The biggest question mark will be that his kit is called "press kit", and I remember press kits as something that works quickly but does not necessarily last very long.
     
  8. sehrgut

    sehrgut Member

    Messages:
    79
    Joined:
    Jan 18, 2013
    Shooter:
    Medium Format
    Don't freeze or chill photochemical working solutions. The risk of precipitate formation and incomplete redissolution of that precipitate is quite real.
     
  9. Rudeofus

    Rudeofus Subscriber

    Messages:
    2,586
    Joined:
    Aug 13, 2009
    Shooter:
    Medium Format
    Also note that while lower temperatures might slow down some adverserial reactions, a lot more oxygen dissolves in cold water than in warm water ...
     
  10. sehrgut

    sehrgut Member

    Messages:
    79
    Joined:
    Jan 18, 2013
    Shooter:
    Medium Format
    Which is why many developer recipes specify boiled-and-cooled water: much of the dissolved gas content will be driven off.
     
  11. RPC

    RPC Member

    Messages:
    624
    Joined:
    Sep 7, 2006
    Shooter:
    Multi Format
    I have never used Tetenal C-41 but I use Kodak's C-41 and if stored in full, glass, well sealed bottles the working solution will last many months. In fact I have had it last over three years without degradation, hardly changing color. This is in contradiction to Kodak's own literature. I would suggest you try storing the Tetenal this way and monitor it occasionally for color change due to oxidation until you need to use it. Then you will know once and for all if it will keep that way.