Dokumol formula

[David Allen]

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.

 

[Ian Grant]

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

 

[David Allen]

Dear Ian,

Thank you for your comprehensive and informative reply.

David.