Colour Paper Development

Discussion in 'B&W: Film, Paper, Chemistry' started by timagal, Oct 4, 2012.

  1. timagal

    timagal Member

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    I have come across a considerable stack of colour paper and some colour developer.

    Unfortunately, it has been very difficult for me to get hold of blix for paper, although I have all the necessary B&W chemicals.

    Is there any way I could bleach and fix this paper using any alternative method?

    Thank you.
     
  2. David Lyga

    David Lyga Subscriber

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    After development in color paper developer I stop, then fix, then, in full room light after the fix, I bleach in potassium ferricyanide (try 1 gram per 200 ml water) for about a minute. Then, briefly back into the same fix for about 10 seconds. Works fine for me.

    To conserve chemistry, you might water rinse briefly before entering the bleach because fixer destroys the potassium ferricyanide after about 20 minutes. However, the few drops of bleach entering the re-fix will not harm the fixer.

    timagal: Potassium Ferricyanide is a 'B&W chemical' used for Farmer's reducer. - David Lyga
     
  3. perkeleellinen

    perkeleellinen Member

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  4. timagal

    timagal Member

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    David, I couldn't be happier with your answer: as it happens, I do have a few pouches of Farmer's Reducer for my B&W film. What is the dilution you would recommend? Farmer's is reputed for its very short life, for how long do you usually store it, and under what conditions? Also, would you have any advice for printing with colour filters but no colour head?

    Steve, are you Finnish?

    Thank you both immensely for your help.
     
  5. GeorgK

    GeorgK Member

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    Funny - when I ran out of RA4 Blix once, I used exactly the same workflow as David. It worked fine.
    A short expanation might be helpful:
    1) The first fix removes the undeveleoped silver halide and makes the picture "stable". The print now consists of developed colour couplers and metallic silver. You can even let it dry (after rinsing) to collect the prints for the final bleach/fix steps. Prints will look dark and dull at this step because of the silver masking the colours.
    2) The potassium ferricyanide bleach turns the metallic silver into silver halide. Rinse thorougly afterward, to avoid contamination of the fixer with ferricyanide (it makes it unstable)
    3) The final fix removes the remaining silver halide.

    To make it work reliably, you will have to add potassium bromide to the ferricyanide. I do not have the exact numbers at hand, just google for "ferricyanide bleach".
    As usual: be careful with the ferricyanide and do not bring it in contact with strog acids (for details: consult the web).

    Ferricyanide bleach alone keeps (almost) forever; only the mixture with thiosulfate ("farmer's reducer") is very short-lived.

    Georg
     
  6. timagal

    timagal Member

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    Georg, I deduct from you answer -which I thank- that I cannot use the Farmer's Solution for this purpose, just the Potassium Ferricyanide: I am back to square one, unfortunately.
     
  7. Mike Wilde

    Mike Wilde Member

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    I seem to recall the Farmers in little Kodak packets had two envelopes. You want the orange one only. That is the k-ferri. My ferri based bleaches tend to get 1 kbr per 4 k-ferri's by weight.
     
  8. timagal

    timagal Member

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    I'm out of luck, Mike: I only have a nearly full box of Tetenal Farmer's... I think I'll have no choice but to order either the Potassium Ferricyanide or the normal blix. Speaking of which: would colour film blix work?
     
  9. Rudeofus

    Rudeofus Subscriber

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    Of course you can use Farmer's reducer, it is basically a BLIX, which means you may not even need the second fixing step. Its biggest disadvantage is its short lived working solution, which means you have to replace it a few times during a longer printing session. I don't know Tetenal's version of Farmer's reducer, maybe they modified it and it works longer. Check out their data sheet. Since you can BLIX in daylight, you can dial in the process as you go.

    Color film BLIX will most likely work for RA4 but may be overkill.
     
  10. cmacd123

    cmacd123 Subscriber

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    Classic Farmers Reducer is a two part solution which has both the beach and Fixer, which only has a few moments shelf life once mixed. Is the Tetenal a one or two part product?
     
  11. Rudeofus

    Rudeofus Subscriber

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    I did several searches of both Tetenal's web page and the WWW, and I didn't see anything about a Tetenal Farmer's reducer. Could someone provide a link to this product?
     
  12. timagal

    timagal Member

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    Rudeofus, thank you for you answer: thanks to you all, there is light in the end of the tunnel again.

    Tetenal Farmer's Reducer is a single compound, and the colloid is indeed very short lived, it will not last more than 20-30 minutes.