Alkaline fix/stop

Discussion in 'B&W: Film, Paper, Chemistry' started by Blighty, Oct 11, 2004.

  1. Blighty

    Blighty Subscriber

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    Does using an alkaline fix necessitate the use of an alkaline stop bath. I have seen these marketed, but they seem somewhat pricey. Is there a formula for such. I know that a water rinse (or rinses) after development is one alternative method. Unfortunately, I have no running water in my darkroom nor the space for x amount of rinse trays. Regards, BLIGHTY.
     
  2. Tom Hoskinson

    Tom Hoskinson Member

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    If you are developing and fixing film a water rinse should suffice (water as the stop bath).

    Exceptions are films (and paper) developed for very short periods of time and/or films and papers that require a highly active developer. For these, use an acid stop bath. The acid stop bath can be followed by a water rinse and/or a simple alkaline bath (like 20 grams of Sodium Sulfite in a liter of water).
     
  3. Blighty

    Blighty Subscriber

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    Thanks Tom! I should have mentioned that I was referring to printing. Regards, BLIGHTY
     
  4. john_s

    john_s Subscriber

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    I use water rinse instead of acid stop for printing, but it does need to be a good rinse. If you don't have enough water, you could try a quite dilute acetic acid stop, maybe 1/4 normal strength. It will become exhausted rather quickly, but it might be a useful middle of the road position. The small amount of acid carried over into the fixer would have minimal impact on its health and capacity, but I suppose it would depend on how much use you want to get out of your fixer.

    It is said that incompletely rinsed developing agents in the paper can contine to develop in an alkaline fixer. For this reason, I think that a neutral fixer could be safer than a quite alkaline one. I think I have read that TF-4 is rather less alkaline than the public formula TF-3. I use a neutral fixer made primarily for colour work (Agfa FX-Universal) and Kodak make one similar. They are cheap.

    Alkaline stop baths are mentioned in one of Troop's books, but they are quite esoteric. I've not heard of anyone actually using one.
     
  5. Andre R. de Avillez

    Andre R. de Avillez Member

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    I'm a bit interested in this thread, as I'll be using TF-3 in my next printing session, and I've got a question:

    Could a sodium sulfite bath be used as an alkaline stop? Something like you mentioned above, but as the sole stop bath? Or would a 12x16 tray with a gallon of water, followed by another with a gallon of sulfite solution suffice? Would raising the sulfite concentration, or adding potassium bromide help? (this is for printing with Agfa 120 developer very sensitive to bromide)?

    Thanks in advance,

    André
     
  6. titrisol

    titrisol Member

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    P.gainer said that he usually stops by using fixer.. or not?
     
  7. gainer

    gainer Subscriber

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    When I develop film, I frequently add fixer concentrate to the tank in the amount of 1 ounce to 15 of the developer. This was recommenced years ago by Edwal when their rapid fixer first came out. That means, of course, 1 shot use.

    Most of my prints lately have been for testing one thing or another, none of which is longevity. I have three trays, the middle one with water to start with. I use TF4 and it seems to have no effect on the life of the fixer. I hesitate to use acid stop regularly, though it would probably take considerable carry over of the equivalent of white vinegar diluted 1+3 to change the pH of the fixer.