Will the real Mytol please stand up

Discussion in 'B&W: Film, Paper, Chemistry' started by albada, Dec 14, 2011.

  1. albada

    albada Member

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    I've discovered three formula's for Paul Lewis' Mytol developer (a clone of XTOL). They are:

    Formula #1: Published in The Darkroom Cookbook:
    Water ..................................... 750 ml
    Sodium sulfite (anhydrous) ....... 85 g
    Sodium metaborate 4H2O ........ 4 g
    Sodium ascorbate ................... 12 g
    Phenidone .............................. 0.15 g
    Sodium metabisulfite .............. 3 g
    Water to 1 L


    Formula #2: Published in The Film Developing Cookbook:
    Water ..................................... 750 ml
    Sodium sulfite (anhydrous) ....... 60 g
    Sodium metaborate 4H2O ........ 4 g
    Sodium ascorbate ................... 12 g
    Phenidone .............................. 0.15 g
    Sodium metabisulfite ............... 3 g
    Water to 1 L

    Formula #3: From an apug.org posting:
    Water ..................................... 750 ml
    Sodium sulfite (anhydrous) ....... 60 g
    Sodium metaborate 4H2O ........ 4 g
    Sodium ascorbate ................... 13 g
    Phenidone .............................. 0.15 g
    Sodium metabisulfite ............... 3 g
    Water to 1 L

    Any idea which one is correct?
    For comparison, here's a formula for XTOL which I took from the XTOL-patent which I downloaded:

    Sodium sulfite ........................ 85 g
    DTPA .................................... 1 g (omitted in Mytol)
    Sodium metaborate (8 mol) ..... 4 g
    Sodium isoascorbate ............. 12 g
    Dimezone S .......................... 0.2 g (Phenidone = 0.15 in Mytol due to higher activity?)
    Sodium metabisulfite ............. 3.5 g (= 3.0 in Mytol)

    I'm tempted to say that formula #1 is correct because its sulfite agrees with XTOL (85g), but I wonder if the lower Sodium metabisulfite in it will cause the pH to be too high. Unless that compensates for the omission of DTPA (is DTPA a base?).

    Formulas #1 and #2 differ in sulfite, but I see no change in anything else to adjust pH, making me think one of these must be wrong. Grrr...
     
  2. michael_r

    michael_r Subscriber

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    If I remember correctly, in the Cookbook they indicate that neither Mytol formula is "wrong", they were just two slightly different formulas (different amounts of sulfite). The idea would be for the formula with the lower sulfite to be slightly sharper and the formula with the higher sulfite to be slightly finer grained. However "slightly" is the key word and an understatement at that. The 25g difference is small and the differences between the two formulas in the real world would be more or less trivial.
     
  3. albada

    albada Member

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    Yes, you do remember correctly, and I should have mentioned that note in my posting. Sulfite is an alkali, and changing it will change pH. But I see no other change to compensate for that pH-change, making me think the 85g version will be too alkaline (pH too high). Unless, as you said, the change is too small to matter.
     
  4. Gerald C Koch

    Gerald C Koch Member

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    I wish that I could do a New York accent here -- "Don't worry about it!" The differences in the 4 formulas are not enough to be of concern. Pick one and use it. The last time I looked the definition of photography was the art of taking pictures not obsessing about this developer or that developer.

    Kodak uses the isoascorbate because it is cheaper and slightly more active. The molecular weights of the developing agents Phenidone, Dimazone S, etc are all slightly different as are their activities. Small difference are possible because of this.
     
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  5. michael_r

    michael_r Subscriber

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    Sodium Metaborate is really the alkali activator in these formulas (XTOL is buffered). The small differences in Sodium Sulfite concentration should have no meaningful effect on activity. Gerald is correct - pick either one and go forth.
     
  6. paul ron

    paul ron Member

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    FaGedAboudIt! Dare ya go.. Oh Aeah E I O U.... sump times WHY?

    Why not test all of em, couple a two tree o four, n help everyone here learn sumptin? OOOOooo! :confused:
     
  7. Gerald C Koch

    Gerald C Koch Member

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    This is exactly what I had in mind. I could hear it in my head but didn't know how to transcribe it. Thanks!

    Jerry
     
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  8. Gerald C Koch

    Gerald C Koch Member

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    The change in pH between 60 and 85 g/l of sulfite is not going to be very much. As I said previously you are not going to see much difference in activity among the four formulas.
     
  9. albada

    albada Member

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    I got the point, and I was culturally enriched in the process! :smile:

    Mark Overton