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  1. #21
    Shawn Dougherty's Avatar
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    I just read this in the Diafine PDF:

    "Because Diafine is a true two-bath developer, each film type is developed to a fixed degree of contrast, and changes in the developing times will have no practical effect on the final results."

    This is different than Thornton's Two Bath (not a true two bath), where times definitely have an effect on the final results. I'm now wondering how much the agitation recommendations for Diafine relate to Thornton's given the differences.

    At this point I'm thinking limited agitation in Bath B (5 seconds every minute and let the shadow development do it's thing (this is basically what I have been doing except I was using 15 seconds initial agitation)). And stick to changes in agitation (and time) using Bath A where you have real control over the highlight density.

    Thanks again to everyone for contributing thus far.

  2. #22

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    Normally I agitate by inverting tank, that is by turning tank up side down and back. Applicable to plastic tank which takes only one 120 film reel and to SS two reels tank (If I develop one film I use empty reel so lower reel with film don't move far). Usually I use plastic tank for two bath development; however I didn't notice any difference in result.

  3. #23
    Shawn Dougherty's Avatar
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    Quote Originally Posted by ed1k View Post
    Normally I agitate by inverting tank, that is by turning tank up side down and back. Applicable to plastic tank which takes only one 120 film reel and to SS two reels tank (If I develop one film I use empty reel so lower reel with film don't move far). Usually I use plastic tank for two bath development; however I didn't notice any difference in result.
    Thank you!

  4. #24

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    Quote Originally Posted by Shawn Dougherty View Post
    Jeff and David,
    Thank you both very much for your input. I appreciate it!

    I wonder if either of you could let me know the process by which you arrived at your agitation procedures? Did you hit any bumps or make any interesting observations along the way?

    Thanks again, fellows. =)
    When I do tests (which, these days, is only when a film or paper is changed | discontinued) my goal has always been to limit as many variables as possible and to be clear what I am trying to achieve.

    What I want from a film | developer combination is unobtrusive grain, reasonably high acutance and good tonality.

    When testing a film | developer combination there are a number of things that never vary:

    All chemicals are always at 20˚ C.
    Processing commences with a two minute pre-soak.
    Agitation is always pour in the developer and gently invert the tank 4 times during the first 30 seconds followed by a sharp tap on the bottom of the tank to dislodge any possible air bubbles. Then one gentle inversion every 30 seconds always followed by a sharp tap on the bottom of the tank to dislodge any possible air bubbles.

    By keeping all of these variables fixed I can then concentrate on finding the correct development time.

    With Delta 400 rated at a personal Exposure Index of 200 I found that 5 minutes in each bath of Barry Thornton's two-bath developer gave me a full range of tones with good shadow detail and equally good detail in the highlights. My first tests at 4 minutes produced acceptable negatives that I felt were just a bit on the soft side. Times longer than 5 minutes produced no noticeable benefit as far as what I require.

    Bests,

    David
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  5. #25
    Shawn Dougherty's Avatar
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    Thank you very much, David. I appreciate the time you've taken to spell all of this out for me.
    Last edited by Shawn Dougherty; 08-20-2013 at 12:05 PM. Click to view previous post history. Reason: typo

  6. #26

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    Thornton bath A is essentially D-23 slightly diluted. Certainly 5s/m of agitation is a method recommended for D-23. As I mentioned before development is essentially diffusion controlled. Therefore the user only needs to provide fresh developer to the surface of the film. One or two inversions is sufficient. Any additional agitation will cause problems. The problem with Thornton TB is that it IS temperature sensitive. Therefore time and temperature in bath A is important. A true two bath developer does not have this restriction. Since no development occurs in bath A due to a low pH.

    Diafine uses Phenidone and hydroquinone as the developing agents. Therefore it provides better film speed, contrast and shadow detail than a developer based on Metol alone.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  7. #27
    Shawn Dougherty's Avatar
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    Thanks Gerald!

    Quote Originally Posted by Gerald C Koch View Post
    ...development is essentially diffusion controlled. Therefore the user only needs to provide fresh developer to the surface of the film. One or two inversions is sufficient. Any additional agitation will cause problems.
    Can you elaborate at all on what effect additional agitation would have, and what kind of problems might occur?

    Thanks again for your time and insights with this.

    -----------------------

    Just to be clear, I can understand why a minimum amount of agitation in Bath B would be preferable but I am still unclear about any negatives additional agitation would have in Bath A (being basically a standard developer).
    Last edited by Shawn Dougherty; 08-20-2013 at 12:07 PM. Click to view previous post history. Reason: additional text at bottom

  8. #28

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    Intense agitation in bath B will wash out solution A which is not what you want. I dare to suggest to stick to agitation technique you use and only vary time in bath A. And yes, temperature does affect contrast a lot, so I do adjust my time in bath A according to temperature. Better practice would be to stick to constant temperature as well. Time in bath B is not critical; technically you should give enough time for shadows to be developed and in some time developer will be washed out of emulsion. I usually leave my film for 10 minutes in bath B. However, I should mention that I always use fresh bath B (in my case it is cheap solution of borax 10 g/l). Contaminated with solution A bath B will produce different results and you can, in fact, overdevelop.

  9. #29

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    Not sure what Gerald is getting at here. Certainly agitation that is too violent can cause problems particularly with 35mm roll film, but I fail to see how continuous agitation properly done would ever be problematic. Clearly it can change the curve (to varying degrees depending on the type of developer being used) and may or may not influence edge effects (again, depending on the developer and the film), but I'm assuming this isn't what Gerald means by 'problems'.

  10. #30
    Shawn Dougherty's Avatar
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    ed1k and Michael,
    Yes, as I said, I can understand the reasons to minimize agitation in Bath B.

    But, as you both say, Bath A is seeming like the place (in Thornton's Two Bath NOT Diafine) where one could really use agitation and time to control the highlights. My limited testing has certainly suggested this.

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