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Tetenal E-6 durability

Discussion in 'Color: Film, Paper, and Chemistry' started by Mark_S, Sep 6, 2013.

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  1. Sep 6, 2013 #1
    Mark_S

    Mark_S Subscriber

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    I notice that there is a big price penalty to purchase the Tetenal E-6 chemicals in the 1L kit vs the 5L kit Freestyle charges $66.69 for the 1L kit, and $99.99 for 5L. I used to purchase the 1L kits, and mix all the chemicals, and store them in brown glass bottles - and have had no issues. Because of the high cost of 1L kits, I am thinking of purchasing the 5L kit, and keeping the chemicals in concentrated form and mixing up the working solutions as I need them. The Tetenal instruction manual indicates that the concentrated chemicals are good for 24 weeks after opening. Does anybody know what the process is that is degrading the chemicals? - If it is oxidation, can I extend the life by filling the void above the liquid concentrate with argon or nitrogen such as is used for preserving an open bottle of wine, or is that just a waste of gas?

    Given the price difference, it makes sense to purchase the 5L kits even if I only use 2L out of each kit...
     
  2. Sep 6, 2013 #2
    Roger Cole

    Roger Cole Subscriber

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    I can't say specifically about today's Tetanal but back in the 90s I kept Unicolor E6 for nearly a year by mixing only what I needed each time and squeezing the air out of the concentrate bottles. It might have kept long, that's just how long it took me to use up a gallon kit.
     
  3. Sep 6, 2013 #3
    clayne

    clayne Member

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    If you have the ability to diminish oxygen from which to oxidize with the concentrates should last a long time. The 5L kit is by far the most economical and at around 1.50$/roll a pretty good value.
     
  4. Sep 6, 2013 #4
    BMbikerider

    BMbikerider Member

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    The ONLY chemical that is in danger of going off is the 1st developer. It is also just a little bit conservative to suggest that the life of the chemicals is only a matter of weeks - it is far longer than that. The colour developer does not deteriorate any whare near so quickly as the other. In fact the blix will go off sooner!

    Continue using the brown glass bottles for the 1st developer but decant the developer into bottles of about 100cc and only use one at a time. Glass is far better than plastic for storage and even half filled bottles will at least double the life. I also add small glass beads (From a broken necklace) to the 1st developer to fill the empty space and exclude as much air as possible. I have the remnants of a 1l kit which was 1st opened in February this year and the 1st developer is still only a light straw colour and will work as good as new.
     
  5. Sep 7, 2013 #5
    Rudeofus

    Rudeofus Subscriber

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    Watch out for the Tetenal BX2 component, it will go bad quickly if you don't use protective gas on partially opened containers. BX2 is essentially Ammonium Thiosulfate and Acetic Acid, and the Acetic Acid brings pH down enough that only little oxidation (with associated pH drop) of Thiosulfate is required before it sulfurs out. This bit me in the past, and a quick search reveals that I was neither the first, nor the only one.
     
  6. Sep 7, 2013 #6
    Tony-S

    Tony-S Member

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    What is the shelf-life of unopened Tetanal E-6 kit?
     
  7. Sep 7, 2013 #7
    Rudeofus

    Rudeofus Subscriber

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    It should state an expiration date on the box (what good are 2 years shelf life if it sits on your vendor's shelf for 1 1/2 years?), but if that is any indication: I had one sit in my basement for over a year and it works well.