Ektacolour RA-4 oxidation

Discussion in 'Color: Film, Paper, and Chemistry' started by Jim Taylor, Dec 14, 2012.

  1. Jim Taylor

    Jim Taylor Member

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    Hey all!

    I've got a barely opened 20l (4 x 5l) box of the kodak RA4 developer replenisher rt/lu that's been stored in a cold cellar for the last 2 years. (Not used due to me moving house to somewhere big enough for a permanent DR!!!)

    Part b of the dev has gone blue/black. I seem to remember it being almost colourless when I purchased it. :blink:

    So... My question is this: can I use the dark-coloured part b as is, or is there a home brew part b that I could make so that I don't have to bin the whole lot...

    ... or should I stop being such a tighta**e and ditch this old stuff and buy new?

    The reason I'm asking, rather than just trying it out is because I'm currently constructing said permanent DR... All gear is in storage whilst building work goes on in the cellar and I've got nowhere else dark enough in the house.

    Whilst I'm on the subject, will the accompanying blix (similarly unused) be ok? Am I right in thinking its 'just' a ferrocyanide/bromide blix?

    Furthermore, as a scientist (like so many of us here :wink: ) is there a good reference so that I can really look into the chemistry of colour developers in general, and perhaps (if Kodak haven't kept it secret) some specifics on the kodak RA4 composition
     
  2. perkeleellinen

    perkeleellinen Member

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    Developer B died for the first time on me when I used to just store it in it's original bottle. I then switched to putting it in an amber glass bottle and storing in it the fridge. It still died as did unopened bottles. If you follow the discussion in the second link there's some stuff on how long the developer ought to last and how to read the code to find the manufacturing date.

    David Lyga, here, says that it's fine to use the black developer B. I've never tried as I only get into the darkroom very occasionally at the moment and I've got no time to experiment. What I now do, though, is to mix up all 5 litres in one go and store them in 1 litre pop bottles. A technique I got from APUG member hrst and I've printed with 18 month old developer with no issues.
     
  3. polyglot

    polyglot Member

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    You may be able to buy just that component... but the dev is so cheap you may as well just buy all-new dev. I would expect the blix to be fine.

    Strangely, this stuff is reported to keep better at replenisher-strength, ie mixed up, than concentrates.
     
  4. Jim Taylor

    Jim Taylor Member

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    Thanks for the replies, esp. perkeleellinen - some great info in the links you pointed out. :smile:
    Can't wait to get the DR up and running again and I'll give it a whirl!
    I used one of the opened bottles (kept under CO2) to mix some up at working conc. - it looked fine... and smelled great (love the smell of this dev!!)
     
  5. Mike Wilde

    Mike Wilde Member

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    I have had this happen, and added the black stuff per instruction, and also added a few grams of dry CD-3 I have around from my mix from scratch days.

    The idea was that the CD is what has oxidised in the part b. So add a bit in and see how it works. The stuff calibrated just the same as the good B concentrate with my lici colourstar analyser, standard test negative and the same paper batch , pulled fresh from cold storage.

    I don't try to push it like new stuff. I figure I am pushing fate, and usually use it this way while I am waiting for a new order of fresh stuff to arrive.
     
  6. brucemuir

    brucemuir Member

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    Exactly my experience.
    I just make up 1 Litre pet bottles and store that way.
     
  7. David Lyga

    David Lyga Subscriber

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    Part B is the nastiest part the the RA4 process. SOMETIMES if black it can be used but only SOMETIMES. If it is not COMPLETELY black there will be a grace period involved. But, to ALL: please make certain to keep this B part COMPLETELY airtight, either in PET plastic or glass, filled to the very rim of the bottle. It should NOT turn dark. Also, Part A must be kept airtight. Part C CANNOT be kept in PET plastic because it will eat at the sides of the bottle. That is due to the extreme alkalinity of Part C. (NOTA BENE: to avoid confusion: Part C of the C41 CAN be kept in PET plastic but NOT the Part C of RA4)

    Of course, if all three parts of RA4 are mixed into your working solution that solution can be kept in PET plastic. - David Lyga

    You know, Polyglot, you just might be right: "Strangely, this stuff is reported to keep better at replenisher-strength, ie mixed up, than concentrates."
     
    Last edited by a moderator: Dec 21, 2012