Solution for tone B (red brown) 5 vols.
Solution for tone H (blue) 1 vol.
Time of Toning 3 to 4 minutes at 65 degrees to 70 degrees F.
The instructions regarding method of procedure, life of bath, etc., are exactly the same as for tone B.
Tone F
Tone F (Sulphide)
Positive Employed
With a thin positive a warm brown tone is obtained, while with denser film the effect is that of a blue-black tone.
| Avoirdupois | Metric | ||||
| 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.