Microphen
The formula of Microphen has never been published but is similar to ID-68, the only difference is packaged Microphen contains a small amount Metabisulphite in Part A to stabilise and help prevent oxidation of the developing agents and the buffering is adjusted slightly to compensate for the effect of the Metabisulphite on the pH of the working developer. In practice ID-68 and Microphen and their replenishers are inter-changeable.
ID-68 Ilford "PQ Fine Grain" Developer
Sodium Sulphite (anh) 85 g
Hydroquinone 5 g
Borax 7 g
Boric Acid 2 g
Poassium Bromide 1g
Phenidone 0.13 g
Water to 1 litre
To use: FS, 1+1, 1+3
Ilford state this formula is similar to Microphen.
ID-68R Replenisher
Sodium Sulphite (anh) 85 g
Hydroquinone 8 g
Borax 10 g
Phenidone 0.22 g
Water to 1 litre
Only FS ID-68 can be Replenished.
There were a number of Ilford PQ variations of ID-11, some have been erroneously assumed in US publications to be Microphen, although there will be some close similarities. However after commercial trials of the PQ version of ID-11 in the late 1950's Ilford decided to retain ID-11 as an MQ developer, and instead introduced two new PQ Fine Grain Developers, Autophen for Photofinishing laboratories based on this research, and Microphen, which was a re-formulation of the PQ Fine Grain deveveloper, with reduced Sulphite, and a different balance of Phenidone and Hydroquinone to improve the developer's characteristics and performance. When Ilford released Microphen they made clear in various publications that it was a new type of developer.
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