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  1. #1

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    Tri-X HEAVY base fog w/rodinal+sodium ascorbate

    Have a friend trying Rodinal with Sodium Ascorbate using the NEW Tri-X. Talk about lousy, the base fog is so heavy the negs are useless. As a control he re-shot two rolls & processed one in D76 & the other in a different batch of Rodinal with Sodium Ascorbate. The negs in D76 are clean & nice looking. Those in the Rodinal solution are as bad as the first.

    He is using the Rodinal combo with HP4+ & gets clean negs with no problems. Is this a problem specific to the NEW Tri-X???

  2. #2
    gainer's Avatar
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    I don't know about the Tri-X, but there can be heavier fog because the pH of Rodinal is high enough to activate the ascorbate even if there were no p-aminophenol. I found that a small amount of borax added to the working solution will reduce the pH and the fog. A teaspoon or so per liter should do it. Development time will be increased about 20%. The borax combined with the hydroxide forms a buffer. It's worth a try. You might like it.
    Gadget Gainer

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    gainer's Avatar
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    I should add that the borax will reduce the fog without appreciable change in effective film speed. Bromide might also reduce the fog, but with some loss of speed.
    Gadget Gainer

  4. #4
    Les McLean's Avatar
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    What are the dilutions and temperature of the Rodinal, higher temperature, 24c plus and and strong dilutions 1 to 15 or stronger will increase the base fog. I dev Delta 3200 at 1 to 10 24C and get base fog but not as much as you describe

  5. #5
    titrisol's Avatar
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    Ascorbate is guilty for raising the fog level on Tri-X
    As P.Gainer Said the pH of Rodinal is quite high (NaOH) thus it'll activate the ascorbate a lot. Try buffering the solution with borax
    I haven't tried adding ascorbate to my Rodinal but that's what I read, it's even mentioned @unblinkingeye.com in Ed Buffalloes article about Rodinal

    Begone, Fog!

    by Patrick Gainer

    Users of Rodinal 1+50 laced with Vitamin C have reported two difficulties. The first is inactive developer, caused by use of ascorbic acid instead of sodium ascorbate. The second is excessive base fog, which appears to be a result of the rather high pH of the Rodinal. Rodinal uses potassium hydroxide as the accelerator and p-aminophenol as the sole developing aent. As produced by AGFA, it is a clean developer admired by some for its "honest" grain. It contains very little sulfite in the working dilutions. Adding sodium or potassium ascorbate makes the developer considerably more active, as p-aminophenol and ascorbate form a superadditive pair. The ascorbate alone is very inactive unless pH is very high, and then it produces high fog level.

    The pH of Rodinal at 1+50 is apparently high enough to activate the ascorbate even if the p-aminophenol were left out. High base fog is the result. Although it is possible to print through the fog, graininess is increased by developer induced base fog. This is not Honest grain.

    We can get rid of it by adding borax. That would seem to be wrong. How can adding more base reduce the pH? Borax is a good buffer. Its pH in solution will not change much from 9.2 over a wide range of dilutions. It reduces the pH of a sodium or potassium hydroxide solution. Borax is cheap and available at supermarkets everywhere as 20 Mule Team Borax (NOT Boraxo). It is easily added to a working solution of Rodinal and dissolves rapidly at working temperature. Only1 gram (1/4 teaspoon) of borax per liter of 1+50 working solution with ascorbate will dramatically reduce the fog level. Developing time will be about 20% greater than that for Rodinal 1+25 without ascorbate. Grain will be finer. I found no virtue in using 2 or 4 grams per liter. Grain may be finer yet, but film speed is lost.
    Even though unadulterated Rodinal produces clean negatives, 1 gram of borax per liter of 1+50 working solution reduces fog slightly and reduces graininess a bit as well. You might in fact prefer the borax treatment over the vitamin C, and almost certainly will prefer it over Rodinal + sulfite. If you try it, use the 1+50 dilution with 1 gram of borax per liter. If you feel the need of more dilution, cut the 1+50 with water after you add the borax until you find out if that is good enough.
    Mama took my APX away.....



 

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