Dokumol formula

Discussion in 'B&W: Film, Paper, Chemistry' started by David Allen, Nov 26, 2011.

  1. David Allen

    David Allen Member

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    Does anyone know the formula for Dokumol? - it has been my print developer of choice for very many years and is the only chemical that I currently do not make myself.
     
  2. Ian Grant

    Ian Grant Subscriber

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    It's a fairly standard Contrast PQ developer and like most commercial liquid print developer formulae contains a mixture of Potassium Carbonate and Sodium Hydroxide as the alkali, in this case with a bit of Borax to buffer it. As it gives cold tones it'll be low in Bromide.

    A good starting point would be Ilford's ID-55. This is a document paper developer.

    Ilford ID-55


    Metol . . . . . . . . . . . . .. . 2 g
    Sodium Sulphite anhyd . . 40 g
    hydroquinone . . . . . . . . 12.5 g
    Sodium Carbonate . . . . . 72 g
    Potassium Bromide . . . . . 1.5 g
    Water to . . . . . . . . . . . . 1 litre

    Use 1+3

    This is a clean working High Contrast developer for document and photomechanical apers so similar to Dokumol.


    I make up all my print developers as concentrates now with Potassium Carbonate and Sodium Hydroxide as this allows concentrates that don't precipitate/crystalise and they keep fairly well.


    PQ Document paper developer
    Concentrated Stock Solution.

    Phenidone . . . . . . . . . . . . . . . . . 1.25 g
    Sodium Sulphite (anh) . . . . . . . . .125 g
    Hydroquinone . . . . . . . . . . . . . . 30 g
    Potassium Carbonate . . . . . . . . . 115 g
    Sodium Hydroxide . . . . . . . . . . . 6.4 g
    Potassium Bromide . . . . . . . . . . . 5 g
    Benzotriazole (1% soln) . . . . . . . 50 ml
    Water to . . . . . . . . . . . . . . . . . . 1 litre

    Use 1+9

    German companies tend to use a different ratio of Potassium Carbonate to Hydroxide and Dokumol actually has more Hydroxide than my suggested alternative above. You could possible use 30 g Potassium Carbonate and 20 ml Sodium Hydroxide but I found that the keeping properties are impaired and it's the same with commercial developers as well.

    In addition Dokumol contains Borax which forms Sodium Metaborate with Hydroxide.

    Ian
     
    Last edited by a moderator: Nov 26, 2011
  3. David Allen

    David Allen Member

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    Dear Ian,

    Thank you for your comprehensive and informative reply.

    David.