_A._ Potassium Ferricyanide 8 lbs. 5 ozs. 4000 grams
Potassium Bromide 2 lbs. 2 ozs. 1000 grams
Water to 50 gals. 200 liters
_B._ Sodium Sulphide (crystal) 2 lbs. 2 ozs. 1000 grams
Water to 50 gals. 200 liters
A trace of iron in the sodium sulphide will do no harm providing the
solution is boiled and the precipitated iron sulphide allowed to
settle before use. The well washed positive is thoroughly bleached in
A, washed for 5 minutes, and immersed in solution B until the film is
thoroughly toned.
_Temperature of Toning_—65 degrees to 70 degrees F.
_Time of Toning_—Four to five minutes.
_Time of Washing_—Ten to fifteen minutes.
_Life of Baths_
The toning baths A and B are comparatively stable and will keep until
exhausted.