RA4 blix white precipitation

Discussion in 'Color: Film, Paper, and Chemistry' started by movin, Jul 16, 2013.

  1. movin

    movin Member

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    Some of my bottles of mixed RA4 blix (Kodak Ektacolor) are showing a yellowish-white precipitation. Some of it forms a solid block at the bottom of the bottle, some crystals are still floating around and give the blix a muddy appearance. Does anybody know what this is and why it has formed? Has the blix gone bad or is it still usable?

    thanks
    Movin
     
  2. Rudeofus

    Rudeofus Subscriber

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    It appears that the fixer has decomposed and precipitated Sulfur in the process. This unfortunately means for you that the BLIX no longer works and must be replaced :sad:
     
  3. Wolfeye

    Wolfeye Subscriber

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    I have the Colortech Tetenal RA-4 kit and my blix, part 2, has the same consistency. Lots of undissolved white particles. I heated it up to 102f before mixing and shook it thoroughly, and the prints came out ok. I do wonder though, about their longevity.
     
  4. Rudeofus

    Rudeofus Subscriber

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    The problem with Tetenal's BLIXes is that their BX2 part is essentially Ammonium Thiosulfate and Acetic Acid. Normally, if Thiosulfate oxidizes, it becomes more and more more acidic, until, below some pH threshold, it decomposes into Sulfite and Sulfur. With Acetic Acid already in the mix, it doesn't take much oxidation before that threshold pH is reached. That Sulfur is the precipitate you saw.

    Depending on your willingness to home brew, you can replace that BX2 part with raw chemicals, or you just get a new kit.