Ilford published a Phenidone - Pyrogallol variation of their ID-4 developer formulae in the original 1941 Kendall Phenidone Patent:

[SIZE=4]Example 3[/SIZE]


Part A
Phenidone 0.4 gm.
Potassium Metabisulphite 12 gm.
Pyrogallol 12 gm.
Water to make 1 litre


Part B
Sodium carbonate (anhyd.) 75 gm.
Water to make 1 litre


To use 1 Part A + 1 Part B
Similar in use to a Developer containing 4 gms of Metol



Obviously quite different to D-512 which has a far higher proportion of Phenidone needed for a balanced Super-Additive effect, Pyrogallol was also used in developers as an oxygen scavenger.

Ian