Farmer's Reducer R4b

Proportional: for overdeveloped film

Part A
Water500ml
Potassium Ferricyanide7.5g
Water to make1000ml
Part B
Water500ml
Sodium Thiosulphate (Hypo)200g
Water to make1000ml
Mixing Instructions: Add chemicals in specified sequence.
Dilution: Use parts A and B separately.
Usage: Immerse a wet negative in Part A for 1-4 mins, agitating gently. Watch the action carefully and remove the negative as soon as the desired density is achieved. Then immerse in Part B for 5 mins, remove and wash thoroughly.

Notes 

This process may be repeated as required.

For general fogging, dilute Part A with 50% water.

Both solutions have a long shelf life and can be stored for future use.