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  1. #1

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    RA4 without stop bath

    I process RA4 paper in a drum, and I'm trying to speed the process up a bit - I can't afford a roller transport processor! I currently mix my own developer but use Kodak bleach-fix. I also use an acetic acid stop bath in between.

    Is it possible to eliminate the stop bath without problems? What can I anticipate? It would save a bit of time to go straight from developer to Blix.

  2. #2
    markbarendt's Avatar
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    It works fine but I have found that using stop and fix makes my blix last longer and I have a lot fewer failures. I also use a pre rinse before the developer.

    What temp are you using?
    Mark Barendt, Beaverton, OR

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  3. #3

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    Hi Mark - it's a bit of a long story. I use 98 deg F or thereabouts, but right now I'm using a slightly modified developer (10mg/L benzotriazole and 3ml/L hydrogen peroxide). This is because I have 1,000 sheets of Fuji Crystal Archive C 8x10 of dubious prior storage that had a bit of yellowish base fog, and the modifications remove the base fog and punch up the contrast a bit with outstanding results. Anyway, I am finding that developing for 2mins instead of one gives best results with these mods and this paper. From what you say, it probably isn't worth removing the stop.

    I also pre-rinse to bring the drum up to temp.

  4. #4
    markbarendt's Avatar
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    I'd definately keep the stop. That's only 30 seconds fill, run, and dump for me.
    Mark Barendt, Beaverton, OR

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  5. #5
    Rudeofus's Avatar
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    Using a stop alone might be a lengthy procedure with no immediately visible purpose, but using a stop&fix as suggested by Mark will improve BLIX life. Such a stop&fix is dirt cheap and easily mixed from 200 g/l Sodium Thiosulfate, 50 g/l Ammonium Chloride and 20-50 g/l Sodium Metabisulfite (Agfa 304 recipe with optional extra Sodium Metabisulfite). Remember that BLIX rarely runs out of bleaching ability but quickly exhausts its fixer component, so taking away Silver Halide before BLIXing will help a lot.
    Trying to be the best of whatever I am, even if what I am is no good.

  6. #6

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    Interesting idea, stop & fix - would the 200g be for the crystalline version of sodium thiosulfate?

  7. #7
    Rudeofus's Avatar
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    AFAIK the Agfa 304 recipe uses 200 g/l of the crystalline version (Na2S2O3 * 5H2O).
    Trying to be the best of whatever I am, even if what I am is no good.

  8. #8

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    What purpose does the ammonium chloride perform in stop & fix?

  9. #9
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    Quote Originally Posted by newcan1 View Post
    What purpose does the ammonium chloride perform in stop & fix?
    It substitutes for the sodium with the thiosulfate; it's basically a way of getting something a bit like rapid fixer (ammonium thiosulfate) if you only have access to sodium thiosulfate.

    As to the original question, the Kodak docs do say that the pre-blix stop+wash steps are optional for RA4 and that you run the risk of magenta streaking if there is any developer carry-over into the blix bath; it can be avoided with careful squeegeeing in a roller processor but is practically inevitable with a drum. Developer will also raise the blix pH and reduce its effectiveness.

    A stop+fix step will certainly help your blix out, but given its price ($2.50/L) and replenishment rate of 10mL/sheet (2.5c!), I really don't think it's worth spending any extra to make a special fixing stop bath. I'm pretty sure that my blix (or I!) will die of old age before it runs out of its 2000 sheet capacity...
    Last edited by polyglot; 02-24-2013 at 07:55 PM. Click to view previous post history.

  10. #10
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    Don't use a fix after the stop. Use the blix. The life will be longer and the results will be more constant, from print to print.

    PE

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