If you really serious--
"The Agfa Book of Photographic Formulae";1910-

Dilution was 1 to 15-20 parts water with three drops per ounce of solution of 10% Potassium Bromide. For really "delicate tone simular to Platinum" use 1 to 100 dilution. Good Luck. So far I've give this out too two other people and no one has tried it yet.