need advice on formulating a new two-bath developer

Discussion in 'B&W: Film, Paper, Chemistry' started by H. G. Hart, Apr 7, 2004.

  1. H. G. Hart

    H. G. Hart Member

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    I use BTZS Tubes to process my sheet film at home and a JOBO Expert Drum at school. I am looking for a new developer to use in these situations. I like the consistent developing provided by two-bath developers with their compensating effects. I have not been able to get quite the degree of sharpness I desire though. I have been considering mixing something of my own up but need the advice of those more experienced with chemistry. What follows is basically a canibalization of FX2 which I like quite a bit, into a divided developer:

    Bath A:

    Metol 2.5g
    Glycin 7.5g
    Sodium Sulfite 35g

    Bath B:

    Sod. Metaborate 100g


    Ideally some development would take place in the first bath so i could have some control over contrast, though I don't know if the first bath has high enough alkalinity. Increasing the sulfite might result in the glycing becoming "excessively solvent" according to Anchell/Troop.

    I also considered the addition of sodium bisulfite (5g) to bath A, and sodium carbonate (10g) to bath B.

    Obviously the best way to see the results is to test, but as a student I don't have a whole lot of extra time to spend testing, so I'd at least like to make some educated guesses about the results before I commit the time and money.

    Thanks in advance.
     
  2. Ka

    Ka Member

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    You should ask Ole, he's a chemist... among other things.
     
  3. mobtown_4x5

    mobtown_4x5 Member

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    wow, you are way further down the road than I am, but it is really cool to see someone trying to experiment with stuff like this, I hope to be there someday...

    Have you tried asking Sandy King?

    Matt
     
  4. Ole

    Ole Moderator Staff Member Moderator

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    I'll have to think about this one a bit, especially after I get home to my books.

    But on first glance it seems to me that the alkalinity of the first bath is high enough the a lot of development will take place. The sulfite isn't enough to be strongly solvent (that's usually said to need 100 g/liter), but it still looks a bit like D-23 with glycin.

    The alkalinity is more dependent on the type of alkali than the amount (within reasonable limits), so there is no significant difference in the development taking place with 35g or 100g - or even 10g - of sulfite.

    Fx-2 is an interesting choise for "splitting". I have been thinking along similar paths, but (still without a single test) am now leaning towards a metol-pyrocat developer. I'm also experimenting with replacing metaborate with bicarbonate for availability reasons (bicarbonate: supermarket, metaborate: mixed from borax - chem. supply house - and lye - supermarket).
     
  5. Joe Lipka

    Joe Lipka Member

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    Been using D-23 (two bath) for a long time, but no glycin. The first bath doesn't do very much in terms of development. When the alkaline bath kicks in, the development accelerates.

    If you want density with this formula, you have to develop a long time because this developer creates "long scale" negatives not real contrasty ones.
     
  6. Tom Hoskinson

    Tom Hoskinson Member

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    I have been fiddling with the idea of using a dilute Pyrocat-HD "A" solution as the first bath, followed by a dunk in a "B" bath with either: (1) Carbonate. (2) Metaborate (3) Borax.

    This would be a split one-shot. I am testing it with Special purpose high contrast films like Kodak Tech Pan and Efke 25.

    However, for high acutance compensating development in normal pictorial photography; I will stick with Pyrocat-HD and either minimum agitation or stand development. I use both methods, depending on the film and the SBR.
     
  7. H. G. Hart

    H. G. Hart Member

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    Maybe I have overthought this a little. It occured to me that maybe I should just split the potassium carbonate, a la dd-76, and put half in the B bath with the metaborate or potassium carbonate crystals as are indicated in the fx2 formula.
     
  8. Tom Hoskinson

    Tom Hoskinson Member

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    I would not be inclined to put additional alkali in the "A" bath.

    You have listed:

    Metol 2.5g
    Glycin 7.5g
    Sodium Sulfite 35g

    (water to 1 liter???)

    35 grams per liter is enough Sodium Sulfite to make your proposed "A" solution into a weakly active developer and it also performs an important developing reagent preservative function.

    If you add bases like carbonate and/or metaborate, the Metol and Glycin will begin to oxidize and the solution will become an active developer - you will essentially turn your "A" solution into a reasonable facsimile of FX-2.

    Try it out. Take a small piece of film and expose it to room light. Develop it for 3 minutes in the "A" bath (no added alkali) only, fix it and inspect it. The amount of increase in density (if any) over base + fog density will answer the question (an eyeball evaluation should do it). Then perform the same test again with 3 minutes in the "A" and 3 minutes in the "B", fix and compare.