What would restraining do for D-76...is it the same as replenishing?

Discussion in 'B&W: Film, Paper, Chemistry' started by streetshot, Sep 18, 2011.

  1. streetshot

    streetshot Member

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    Are these processes different or are they the same? Currently I'm replenishing D-76 for Tri-X (and HP5+) and recently heard about restraining. Is it the same as replenishing or is it different. If different how does one restrain D-76?

    With thanks for an amazing forum.

    Michael
     
  2. Monito

    Monito Member

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    Not the same as replenishing. It means to restrain or hold back an active or over active developer. (Replenishing means to add new developing agent to exhausted developer as an economical alternative to making fresh developer.) I think restraining is done with bromide sometimes added to the mix. I'm sure there are other restrainers too. I think it is for less acutance (edge sharpness due to Mackie lines) and finer grain, but I'd have to look it up. Bump for you because I'm interested to hear what others more knowledgeable have to say.
     
  3. panchro-press

    panchro-press Member

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    NO!
     
  4. johnielvis

    johnielvis Member

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    well----could be---when you replenish, the existing restrainers in the developer may "build up" over time....so you effectively end up with a different developer recipe with more of a percentage of the restrainer remaning....

    very difficult to determine the outcome without the specifics.
     
  5. streetshot

    streetshot Member

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    Thanks John. You open an interesting question about how much restrainer builds up through the replenishment cycle(s).

    The specifics - or as specific as I can be are this...I add .75 oz of D76R (now L76R) for each roll developed to the D76. Thats the process...in other words, when I develop 8 rolls in an 8 roll tank I pour the D76 back into its bottle and add 5-6 oz. of the replenisher to the bottle. I generally get between 90 and 100 rolls from a gallon of stock developer with replenishment.

    Am I effectively restraining the developer...or some other/similar effect?

    With thanks,

    Michael
     
  6. Monito

    Monito Member

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    Shoot two short rolls with some test shots of a target you make, including a step wedge, gray card, colour chart, and some colourful items that you can set aside. Use very repeatable lighting, such as high noon outdoors, or flash with fresh batteries, waiting double the recycle time between flashes, or incandescent light, either one at an accurately measured distance. Include a note in the shot saying whether it is roll #1 or #2.

    Develop one roll at the beginning of a batch. Run your 90 or so rolls through and develop the second roll as the last one.

    Compare, perhaps by printing the two (35mm?) strips side by side in a 6x7 negative carrier onto the same piece of paper.
     
  7. Photo Engineer

    Photo Engineer Subscriber

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    Ideally, a fresh developer should equal a seasoned developer. This is why in color you add a "starter" to make this outcome take place. In B&W, the seasoning effect is much less pronounced and the build up in halides in the developer have far less impact on the resulting image.

    Generally though, Iodide salts and Bromide salts are restrainers and also can repress edge effects. Included in this list are PMT (Phenyl Mercapto Tetrazole) and BTAZ (Benzotriazole). There are many many more. The initial effect is lower fog, then lower speed and contrast.

    PE