Two-bath Microphen?

Discussion in 'B&W: Film, Paper, Chemistry' started by varjag, Aug 22, 2005.

  1. varjag

    varjag Member

    Messages:
    25
    Joined:
    Apr 11, 2005
    Location:
    Bergen, Norw
    Shooter:
    35mm RF
    Anyone here tried to come up with two-bath variation of Microphen formula? My understanding is that it is necessary to separate alkali into the second bath; however what should I do with bohric acid?

    Also, how two bath version would behave in comparision to the original? Would it still be good old Microphen or should I expect entirely different characteristics?
     
  2. Tom Hoskinson

    Tom Hoskinson Member

    Messages:
    3,879
    Joined:
    Mar 7, 2004
    Location:
    Southern Cal
    Shooter:
    Multi Format
    You might try something like this:

    A Solution

    Water 750 ml
    Sodium Sulfite20 g
    Sodium Bisulfite 5 g
    Hydroquinone 5 g
    Phenidone 0.13 g
    Potassium Bromide 1 g
    Water to make 1000 ml

    B Solution

    Water 750 ml
    Sodium Sulfite 85 g
    Borax 7 g
    Boric Acid 2 g
    Water to make 1000 ml

    Would it still be good old Microphen? NO! (this is actually a split version of ID-68 with some buffered sulfite in the A Bath)

    I would try 3 minutes in A follwed by 3 minutes in B.

    Good Luck!
     
  3. varjag

    varjag Member

    Messages:
    25
    Joined:
    Apr 11, 2005
    Location:
    Bergen, Norw
    Shooter:
    35mm RF
    Thank you Tom!

    What is the role of Sodium Bisulfite in this recipe? I don't have it in my formulary handy; can it be substituted by anything?
     
  4. Tom Hoskinson

    Tom Hoskinson Member

    Messages:
    3,879
    Joined:
    Mar 7, 2004
    Location:
    Southern Cal
    Shooter:
    Multi Format
    The sodium bisulfite buffers the sodium sulfite and thus maintains the solution pH. At least, that's the theory. You can leave the sodium bisulfite out altogether - the developer will work without it.
     
  5. Gerald Koch

    Gerald Koch Member

    Messages:
    1,670
    Joined:
    Dec 14, 2004
    Shooter:
    Multi Format
    You can't just separate the ingredients into a Bath A and the boric acid and borax into a Bath B. Bath B has to be rather alkaline whether from borax, sodium metaborate, or even sodium carbonate.

    What I would do is to use Microphen as the A bath and use a B bath made of 10 g/l of sodium carbonate. If this produces too much contrast then use a B bath consisting of 10 to 20g/l of borax. You will need to do some experimenting.

    OR you could just use Diafine.
     
  6. Tom Hoskinson

    Tom Hoskinson Member

    Messages:
    3,879
    Joined:
    Mar 7, 2004
    Location:
    Southern Cal
    Shooter:
    Multi Format
    Not just Borax and Boric Acid in the B bath.

    Sodium Sulfite 85 g
    Borax 7 g
    Boric Acid 2 g

    That should make a sufficiently alkaline B bath. If it isn't alkaline enough, add some more Borax - or Sodium Metaborate - or Sodium Carbonate.