Iron Blue toner is an inexpensive, but effective toner that is equivalent to Ansco Toner 241. The toner will work on most papers. but each type of paper will yield a slightly different tone. Blue toning is a favorite of those photographers working with winter or water scenes. Just a hint of blue enhances the impression of winter snow, and softens an otherwise stark photograph. A number of different formulations for iron blue toners been published. All of the formulations are based upon the formation of Prussian blue. The chemicals in this formula give a brilliant blue tone. To allow you to vary the blue color to a softer, blue-gray tone, this formula also contains borax for the preparation of an afterbath.
A blue-green tone may be obtained by toning the well washed blue toned print in a sulfide bath. The sulfide bath is a 1% solution of sodium sulfide with hydrochloric acid at a ratio of 1 part acid to 50 parts bath. The print is immersed until the color changes to a blue-green. Prints intended for this treatment should be slightly dark. Discard bath immediately after use.
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 Iron Blue Toner.
NOTE: Ferric Ammonium Citrate is somewhat light sensitive and should be stored in the dark or a dark brown container.
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 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; however, a high concentration of strong
acid (such as hydrochloric acid) is not
used in the iron blue toning process.
Succinic is not sufficiently strong to release the cyanide atoms. To
dispose of excess potassium
ferricyanide (solid or in solution), wash the material down the drain
with excessive amounts of water.
MIXING THE STOCK SOLUTIONS
CAUTION: Never use metal utensils or containers in the preparation
of or the use of toning solutions. We recommend you wear a dust mask, splash
goggles, rubber gloves and a rubber apron anytime you are mixing dry chemicals.
Use distilled water. You will need a glass or plastic temporary mixing
container, one with a capacity of 1000 ml to mix the toning solution. You will
also need a 1 liter brown storage container to store the mixed toning solution
and a second 1 liter container if you prepare the
borax after-bath.
TONER WORKING SOLUTION A
| Chemical | Amount | Units |
|---|---|---|
| Distilled Water (120°F/48°C) | 500 | ml |
| Ferric Ammonium Citrate | 8 | g |
| Potassium Ferricyanide | 8 | g |
| Succinic (tartaric) acid* | 37 | g |
| Distilled Water to make | 1000 | ml |
Place the water in the mixing container and add the ferric ammonium citrate. Stir until the solid completely dissolves. Add the potassium ferricyanide and stir the solution until the solid dissolves. While stirring, slowly add all of the 37 grams of Succinic Acid, stir solution until the solid dissolves. Finally add cold water to bring the final volume up to 1000 ml and stir to ensure the solution is mixed thoroughly. Store the toning solution in a brown bottle. Ferric Ammonium Citrate is somewhat light sensitive and, in strong light, will be converted to ferrous ions which will cause the solution to turn dark blue.
AFTER BATH (0.5% BORAX SOLUTION)
| Chemical | Amount | Units |
|---|---|---|
| Distilled Water (68°F/20°C) | 1000 | ml |
| Borax | 5 | g |
TONING THE PRINT
All toners work best if the print is fixed with a nonhardening fixer such
as TF-4 (Cat. No. 03-0141). A hardening fixer decreases the permeability of
the gelatin of the print thus decreasing the ability of the toning chemicals
to reach the silver in the print.
Blue toning will cause some darkening of the final print, the depth of the
blue color is dependent on the silver density of the starting print. Best
results seem to results when the starting print has a density somewhat lighter
than you wish in your final toned print.
To tone the print, immerse the fixed and washed print in undiluted toning
solution in a plastic tray and agitate it. If you start with a dry print, be
sure to presoak it in
water. The longer the print remains in the
toning solution, the deeper the tone. You will have to use test strips to
determine the length of toning time to get the hue or the final tone you wish.
When the print is removed from the toning bath, it will appear blue-green.
Wash the print in running water. The print
will turn blue during this wash. Wash only for a few minutes. Prussian blue
is very slightly soluble in water for an
extended period of time. (Using an extended wash is a good technique to
lighten an overtoned print.)
If your wash water is alkaline, you will
have to use tray washing because Prussian blue is quite soluble in base.
Place 1 or 2 ml of acetic acid from
your stop bath in your tray water to acidify the
water. Use at least two separate tray
washings, changing the water often.
BORAX AFTER BATH
The intense blue color of blue toning can be muted by soaking the print
(after the wash) in a 0.5% borax solution.
Immerse the toned and washed print in the 0.5%
borax solution in a plastic tray. The duration of the soak will determine
the tonal change going from blue to gray-blue.
REFERENCE
Iron Blue Toner Kit No. 06-0020,
Photographers' Formulary (800-922-5255).
Photo-Lab-Index, Section 15, Supplement 173, p. 67.
The Darkroom Cookbook, Stephen
G. Anchell, p.155.