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  1. #1
    Harry Lime's Avatar
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    Barry Thornton 2 Bath - how to adjust for finer grain?

    In light of all the recent talk about this developer I have a question that perhaps some of the more chemistry adept members can answer?

    How would you adjust the formula to achieve finer grain i.e increase the solvent action?

    Thanks

    Bath A
    80 g sodium sulfite
    6.5 g metol
    Make up to 1 L with water

    Bath B
    12 g sodium metaborate (Kodalk)
    Make up to 1 L with water

  2. #2

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    In general, one way to increase solvent action (aside from adding more sulfite up to a point) is to increase the amount of time the sulfite has to act, by lowering the pH. In the case of a true two-bath developer this would be an adjustment to the alkali concentration, or substitution of the alkali (to borax for example) in the second bath. There are other things that can be done. Of course, there are always tradeoffs and altering the formula will change other characteristics such as speed, contrast and sharpness.

    That said, the formula you listed is more like a divided D-23 type rather than a true two-bath developer. A significant amount of development occurs in bath A, so alterations to bath A (very similar to stock D-23) could also be made for slightly finer grain (eg: increasing the sulfite, adding sodium chloride etc). This is already a fine grain developer so getting substantially finer grain would have more to do with film choice than modifications to this developer.

    There are many published variations on the divided D-23 concept which you may want to look into.
    Last edited by Michael R 1974; 11-11-2012 at 09:49 PM. Click to view previous post history. Reason: Typo

  3. #3
    Harry Lime's Avatar
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    thanks.

    Does DD23 deliver full film speed? 400asa out of Tri-X?

    thx

  4. #4

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    use bath B with next formula:
    Borax 10g
    Sodium sulfite 30g
    Water 1l
    this formula allow reuse, because sulfite. give less contrast and fine grain

  5. #5

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    Quote Originally Posted by Harry Lime View Post
    thanks.

    Does DD23 deliver full film speed? 400asa out of Tri-X?

    thx
    There are lots of variations on DD23. Speed will depend a lot on the alkali in the second bath. Generally, replacing the metaborate with borax in your specific case would likely reduce film speed slightly versus the original formula. I have not personally used Tri-X in DD23, but I doubt you'd get full film speed. Then again - your EI has a lot to do with your personal preferences as far as shadow density and contrast are concerned, so it is always difficult to say what speed you will get with any developer/film combination. Testing is the only way, and divided and two-bath developers are no exception.

  6. #6
    David Allen's Avatar
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    I can't imagine why you would need finer grain with BTTB developer as I find it the perfect balance between fine grain, speed and contrast.

    However, if finer grain is your requirement you should increase the Sodium Sulphite to 100g and replace Bath B with Borax (i.e the Stoëckler formula). However, the trade off will be lower contrast and loss of speed.

    Best,

    David
    www.dsallen.de

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    Also look at Anchell & Troop's TD-201. It uses a less metol and more sulfite in Bath A and a combination of borax and metaborate in the second bath. Fine grain, good compensation and film speed, and sharp.

  8. #8
    Harry Lime's Avatar
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    Thanks everyone. I'll play around with these suggestions.

  9. #9

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    The granularity of a film is determined by its formulation. Highly solvent developers can reduce the graininess but at the cost of reduced resolution and speed. Two bath developers with their emphasis on edge effects tend to enhance graininess. If fine grain is your goal then these developers are not a good choice. A developer like Perceptol might be a better shoice.
    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



 

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