Chemistry question

Discussion in 'B&W: Film, Paper, Chemistry' started by kjsphoto, Jul 26, 2004.

  1. kjsphoto

    kjsphoto Subscriber

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    OK,

    I have researched and finally went and ordered some PYROCAT HD. But I was also looking at XTOL and cam across a formula for MYTOL. How good is mytol? I am used to TMAX developer but I want to start mixing my own so it can be more predictable.

    The pyro is for the LF and the mytol would be for MF and 35mm.

    This is the formula I came across and have no idea if it is correct or any good;

    STOCK SOLUTION A
    Chemical Amount Units
    Distilled Water 750 ml
    Sodium Sulfite 60 g
    Sodium Metaborate 4 g
    Sodium Ascorbate 13 g
    Phenidone 0.15 g
    Sodium Metabisulfite 3 g
    Distilled water to make 1000 ml

    USAGE
    Directions for dilutions to equal Xtol diluted 1+1 or 1+2 at 68°F/20°C.

    Also what kind of scale do you recommend?

    Thanks,

    Kev
     
  2. Jorge Oliveira

    Jorge Oliveira Member

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    I've never tested Mytol, but I liked very much E76 dilluted 1+1 or 1+3. I feel results shall be very similar between the two.

    http://www.stanford.edu/~cpatton/yingui/e76.htm

    Ascobic devs are have a very nice balance between fine grain and acutance.

    Nowadays I'm using one of Patrick Gainer's long lasting ascorbate formulas with borax as alkali and sulfite at 25g/liter.
    IMO this is better than no sulfite and a stronger alkali.

    And I believe you are looking for how to measure the minute phenidone quantities.
    Don't.

    Prepare a stock solution of phenidone in very pure alcohol (I mix 2g/100cc) and then 10cc equals 0.2g and so on.
    If possible, dissolve a pinch of hydroquinone in the alcohol before adding the phenidone (it lasts longer this way).

    Jorge O
     
  3. gainer

    gainer Subscriber

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    You can double the amount of sodium ascorbate in Mytol without significant increase in initial activity. That will decrease the amount of developer required to do one roll, or allow you to do 2 or more rolls in the same amount of developer that would only do one before. It will also increase the storage life. The extra ascorbate acts both as preservative and as replenisher. The sulfite may salve your conscience and change gradations, but will not preserve ascorbate as it does hydroquinone.
     
  4. Greg Rust

    Greg Rust Member

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    Mr. GAiner,

    Even though I mix my own developers from scratch, my chemistry background is limited. I'm not confident of my ability to prepare developers with sodium ascorbate or ascorbic acid. A couple of years ago I was successful with your ascorbic acid version of Rodinal. But I haven't tried it since then. I could use some help going from ascorbic acid to sodium ascorbate. Also, is it possible to store the ascorbate for a few months?

    Thanks for sharing your knowledge.

    Greg