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  1. #1
    bobfowler's Avatar
    Join Date
    Sep 2003
    New Jersey, Land of the Living Dead
    Multi Format

    Diafine in rotary processors

    I've heard that Diafine isn't recommended in rotary processors (Jobo, Unidrum, etc). As an experiment, I went ahead anyway and processed some J&C Classic 200 5X7 sheets that I exposed at EI 400 in a Unidrum. The overall negative density was very high, and aside from the negatives being a bit flat (expected), the results weren't too bad at all. The film is a bit grainier than when processed in Microdol-X 1:3 (also expected), but the results were still quite good. A test scan of one negative is here.

    My question: Would it help reduce the overall density if I diluted either or both parts of the Diafine before processing when using in a rotary tube? If so, does anyone have any dilution starting points I can try?
    Bob Fowler
    Some people are like Slinkies. They're really good for nothing, but they still bring a smile to your face when you push them down a flight of stairs.

  2. #2

    Join Date
    Sep 2002
    Willamette Valley, Oregon
    Medium Format
    You might get away with diluting one hell of a lot. I doubt part B
    could be so; all that agitation. Dan

  3. #3
    Donald Qualls's Avatar
    Join Date
    Jan 2005
    North Carolina, USA (transplanted from Seattle)
    Multi Format
    I've used Diafine with Bath A diluted 1:49 for microfilm, to control contrast while still gaining speed; it gives a good EI 100 with Copex Rapid, but the contrast tends to be on the flat side and there's no underexposure latitude at all. Overall density isn't much changed -- Dmax looks very similar to what I get with other films, after allowing for the crystal clear base of microfilm stock.

    Essentially, diluting Bath A means less developer will carry over into Bath B, where it is activated; that will result in increased compensating action and further reduced contrast. Working against that, the constant agitation in a rotary processor may tend to wash the Bath A out of the emulsion too quickly, resulting in reduced development that won't be helped by reducing the amount of developing agent present with dilution.

    Bottom line, diluting Bath A will result in underdevelopment. If your density is too high, rate the film at a higher EI (try 500, 640, maybe even 800). Given that the developer is fully reusable other than carry over loss of Bath A, you might try developing a single 5x7 sheet wrapped inside a double-120 stainless tank without reels, using the recommended agitation (as you would for roll film) and a full tank of liquid, as a comparison. If you find anithalation dye that hasn't completely washed out of the film at the end with this process, rewash in HCA or multiple changes of water, in a tray or similar to clear the dye.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.



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