BROWNISH-BLACK: Sol.A: Tannic acid 1.77 gm
Water 118.4 ml
Sol.B: Sodium carbonate 1.77 gm
Water 148 ml
You can do this immediately after processing and washing of the print or you
can do it later after the print has been dried. If you do it later presoak
the print. Immerse print in sol.A for 5 minutes. Drain it and immerse in
sol.B for 1 minute. If a deep wine colour is not achieved, repeat the
process several times. The print should dry to a deep brownish- black.
DARK BROWN: Sol.A: Potassium hydroxide 1 pellet
Water 148 ml
Sol.B: Tannic acid 1.77 gm
Water 118.4 ml
Immerse the print in sol.A until the blue tint disappears. Wash the print
in clean water. Immerse in sol.B until the print is as dark as you desire.
Wash well and dry.
If you reverse the order a brown ochre print can be obtained.
SEPIA: Sol.A: Tannic acid 1.77 gm
Water 118.4 ml
Sol.B: Sodium bicarbonate 2 gm
Water 100 ml
Immmerse print in sol.A for 5 minutes. Change to sol.B. Repeat several
times if necessary.
The paper stock and intensity of the blue from the original print will
affect the final toning. I recommend keeping a journal, noting paper type,
toning process, and the final result.
An aside- chemicals can be pricy and/or difficult to find. I've turned to
alternatives. I replace the tannic acid solution with 3 regular teabags to
a litre of boiling water. Red wine will also work- the cheaper the better.
Sodium carbonate can be replaced by washing soda and baking soda is just
another word for sodium bicarbonate.
Now I have a question. I recently read an article on the Van Dyck Brown
process. The author stated that, like cyanotypes, these prints can be
toned. He did not give any recipes. If anyone has some to share I would be
oh-so-greatful.
Bill Thoms