For Blue Tones on Bromide Paper.
A split tone effect with deep blue shadows and brown highlights may be obtained by first toning in sulfur-based toner such as Hypo-Alum Sepia, brown, or Polysulfide Paper Toner (Kodak T-8), followed by an iron toner such as Ferricyanide-Iron Blue Toner (IT-6), Blue Toner (GT-14), Iron Blue Toner, or Iron Green/Blue Toner.
FOR YOUR CHEMICAL SAFETY
Potassium Ferricyanide: in spite
of the fact that this compound contains cyanide, it is not particularly toxic.
The reason is that the cyanide groups are bound to the iron atom and are not
free to act as a poison. The cyanide groups can be released as hydrogen
cyanide gas if the Potassium Ferricyanide
is placed in a strong acid solution. To dispose of excess
Potassium Ferricyanide. (solid or in
solution), wash the material down the drain with excess water.
MIXING THE SOLUTIONS
You will need one glass or plastic mixing container with a capacity of at
least one liter to mix the Toning Solution. You will also need a one liter
glass or plastic storage container to store the Toning Solution. If at all
possible, use either distilled or demineralized water to mix the Toning
Solution. Hard water often contains iron ions which will alter the chemistry
of the Toning Solution.
SOLUTION A
| Chemical | Amount | Units |
|---|---|---|
| water (125°F/52°C) | 750 | ml |
| Potassium Ferricyanide | 2 | g |
| Sulfuric Acid (48% conc.)* | 4 | ml |
| Cold water to make | 1000 | ml |
STOCK SOLUTION B
| Chemical | Amount | Units |
|---|---|---|
| water (125°F/52°C) | 750 | ml |
| Ferric Ammonium Citrate | 2 | g |
| Sulfuric Acid (48% conc.)* | 4 | ml |
| Cold water to make | 1000 | ml |
*CAUTION: Always add the acid to the water, slowly, while stirring. NEVER add water to the acid, which may boil violently.
For use, mix equal parts of each solution just before use. The prints, which should be slightly lighter than normal, must be thoroughly washed before toning. They are then immersed in the toning solution until the desired tone is reached. They are then washed until the yellow stain is removed from the whites. If the wash is alkaline, some bleaching of the image may take place; this may be prevented by washing the toned prints in several changes of water, each slightly acidified with a few drops of sulfuric or acetic acid.
REFERENCE
Ferricyanide-Iron Blue Toner (Ilford IT-6),
Photo Lab Index, Section 15, Supplement No. 172, p. 67.