Sepia Toner

Sepia paper toner

Part A
Water1000ml
Potassium Ferricyanide100g
Potassium Bromide100g
Water to make2000ml
Part B
Water500ml
Thiocarbamide50g
Water to make1000ml
Part C
Water500ml
Sodium Hydroxide50g
Water to make1000ml
Mixing Instructions: Add chemicals in specified sequence.
Dilution: Part A is stock solution of Bleach. Mix equal parts B + C, then dilute 1+9 with water to make stock solution of Toner.
Usage: Immerse fully-washed print (presoak if previously dry) in the bleach until it turns a faint buff color. Rinse in several changes of water. Redevelop in toner solution for one minute or until fully redeveloped. Wash.

Notes 

Part A is Bleach, Parts B and C are combined to make Toner

Solutions can be stored for several months in opaque bottles. The working solution should be used immediately or stored for a short period only.

For yellow-brown tones make working solution with half the quantity of B. For deep-brown tones make working solution with double the quantity of B.