Getting decent shelf life from C41 chemicals

Discussion in 'Film and Processing' started by jamie_robertson|2, Jan 24, 2013.

  1. Hi folks,
    I've just finished my first batch of C41 processing using the Tetenal 1 litre kit. See here for kit details:
    If I were to buy the 5 litre kit next time and mix it up in batches of 1 litre at a time do you think the remaining concentrates will have a decent shelf life i.e. 1 to 2 years? Obviously I will expel as much oxygen from the bottles as possible either by using nitrogen or by holding a flame in the neck of the bottle before sealing (note to self: check for volatility of solutions first!)
  2. Are those liquid concentrates? If you want something that has good shelf life before being mixed, get the "press kit" of powdered C-41 chemicals. Shelf life after being mixed is still only a month (maybe two?) but the unmixed powder is good for quite a while, easily two years or more.
  3. The color developer is the sensitive one. I have had mixed Tetenal liquid-based C-41 developer last over 18 months, kept under my sink, with occasional use about every other week.
    Keep the air squeezed out.
    I got 25 rolls from 1 liter before discarding.
    The Bleach/Fix or BLIX will last a long time and can be rejuvenated with vigorous shaking. The stabilizer lasts a long, long time.
  4. Jamie, I missed the point of your post. Personally, I would be confident the concentrate would last even longer than mixed developer.
  5. Thanks. Yes Craig, they are all liquid concentrates. I will look at the powdered kits (if I can find them here in the UK).
  6. the recent scare about no negatives.
    I started seriously looking at a DIY c-41.

    after some reading, I saw thet both the tenatal press kit and the unicolor kit give good results and are easy to use.

    But warnings about the short life of BLIX cause me to look for another kit.

    I found out that both of these kits were based on research to create a working kit.

    that Kodak and fuji had trade secrets that were not shared with other companies.

    that Fuji-Hunt made this kit intended for mini0labs.

    and that the Rollei kit was repackaged Fuji-hunt and used seaparate bleach and fix. this gave longer life to the solutions

    a page I read ( maybe someone has it) explained how this could result in very economical results.

    I spen a half hour talking to a lady ar Pgotograhers formulary.

    and she told me they were haveing problems getting all the parts.

    and how they used an inert gas bubble to prevent oxygen from affecting the chemicals.

    apparently the page I read inb novmeber did not mention that

    and I am guessing with reasonable care one could divide the rollei kit to make it last a lot longer.

    I have not done this and would like to hear from someone with hands-on experience.

    gee only 7 typos
  7. Thanks ever so much guys for all your advice. Bill, I am amazed you got mixed solutions to last 18 months. That's great!
    Although the Tetenal kit uses a Blix instead of separate bleach and fix stages, the concentrated liquid components are supplied separately so should last much longer than the mixed solution. From what you have all said, I think it will be reasonably safe to buy the 5 litre kit and mix it up 1 litre at a time. It only costs the equivalent of getting a lab to process 10 films and should be capable of processing at least 100 films.
    One thing I have wondered is how to recognise when each mixed solution is coming to the end of its life. For example, if I develop a film and it turns out bad, how do I know which of the 3 working solutions is the culprit?
  8. It would be perfectly feasible to use the Tetenal kits but ignore the bleach and fix and buy Kodak or Fuji-Hunt bleach and fixer. That avoids the blix-self-destruction problem.
    No working solution of blix will last 18 months.
    There are no trade secrets in the bleach or fix, just in the developer.
    The Tetenal kits use blix because they are "Press" kits, for working press in the field, doing news photojournalism, and simplicity of the process is paramount. The working life of the blix is irrelevant in this market.
    The Kodak Z-manual on C-41 will tell you how to diagnose failures of each of the stages of processing. Bleach failure shows as retained silver. Fix failure shows as white haze in the film. Developer failure shows in all sorts of ways.
  9. Thanks John, it's the life of the concentrates that I am most interested in. I have no problem dumping mixed solutions after a couple of months but I would hate to have to pour out a 90% unused 5 litre kit after the same length of time. As I said the blix concentrates are supplied as two separate concentrates so I would hope they would last well compared to a mixed diluted solution.
    Thanks for tip on the Kodak Z-manual, I will look for that :)
  10. John Shriver: "No working solution of blix will last 18 months"​
    My personal experience contradicts that.
  11. Thanks Robert, that is very good info.
  12. There is a persistant myth that color developers have a short life. I have gotten more than three years storing both mixed C-41 and RA-4 developers with no degradation. The trick is in minimizing oxidation. You can get this type of longevity by storing the mixed developers in full, glass, well-sealed bottles. I use canning jars of different sizes. For developers, I don't mess with storing concentrates. I mix it all and fill the bottles. Over time it hardly changes color. Bleach-fix (blix) does have a relatively short life, but for C-41 you should be using a separate bleach and fix anyway.
  13. Hi Rob, I know it's an old thread, but I was intrigued by your statement regarding C41 shelf life. You say if the air is completely squeezed out from C41 working chemicals (diluted) I would have a chance to keep them working more than 2 or 3 months? Thanks!
  14. Absolutely. Use a PET (beverage style) bottle, full to the brim and capped tightly. Working solutions will last "a very long time". More than 2 or 3 months.

    Using separate bleach and fixer addresses the comment above regarding short life. Use Kodak Flexicolor chemistry, for example from Unique Photo in New Jersey.
    bogdannicolescu likes this.
  15. I read also that Digibase C41 has also bleach and fix separated and it's based on Fuji Hunt. Do you think its' a good option?
  16. I don’t have experience with chems other than Kodak, sorry. My guess is that separate bleach and fixer from any manufacturer would be better in every way compared to blix.
    bogdannicolescu likes this.
  17. I agree with Wilmarco's comments. Personnaly, I use glass canning jars.
  18. WRT differences between chemistry.
    I've always had good and consistent results with the full Tetenal kits. OTOH, those powdered 'press' kits are designed for convenience and speed, not for quality.

    A slight 'crossed curves' processing error can be tolerated if the negatives are only going to be scanned, but not if they're going to be properly enlarged and printed.
    bogdannicolescu likes this.
  19. Thanks for your answer! That gives me some hope that I could do C41 at home, without the pressure of collecting 16 rolls of film and develop in 1 week all of them. So considering I have a 5 liters kit of C41 chemicals with separated bleach and fix and I am mixing 1 liter at once, also how long I can keep the undiluted chemicals? They also need to be air squeezed and kept in the fridge?

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