Hello

I found Ilford patent US5210010 with PQ formula very similar to MSDS DD-X. Also this formula have same dilution and pH as DD-X. What do you think about this?

Potassium Sulphite 65% 548ml
Water 380ml
Glycol 45ml
Hydroquinone 44g
Phenidone 1.2g
Borax 23.5g
DAPTA 4.8g

dilute 1+4, pH=8.5