Cyanotype toning
Many different chemical substances can affect the cyanotype color. From the procedures edited over the years we list here the ones that are easier to use.
Potassium ferricyanide (Prussian blue) gives the cyanotype prints that typical blue tone, but it can be chemically modified to tone to a different color. Prussian blue decomposes in an alkaline environment and gives iron hydroxide, which is salified with other compounds producing different tones.
You can tone only after at least 24 hours from the printing.
1.Tone a cyanotype dark-brown
Prepare the following solutions:
A dilute 12ml concentrated ammonia in 1liter demineralized water.
B dissolve 60 gr tannic acid in 500ml demineralized water
Wet the cyanotype print in water, immerse it in solution A until it turns to straw-yellow. Wash under running water for 15 min. then move the print to the solution B to tone it. Wash again under running water.
2. Convert to black toning
Prepare the following solutions:
A dilute 0,5ml (about 6-7 drops) of nitric acid 65% in 1 liter demineralized water.
(be careful when you work with nitric acid, it is a strong corrosive and oxidant. It burns the skin and turns it to a yellow color. Wear gloves and safety glasses.)
B dissolve 50gr sodium carbonate in 600ml demineralized water.
C dissolve 50gr gallic acid in 600ml demineralized water.
Immerse your print into water, then immerse it in solution A for a couple of minutes.
Wash for 10 min. under running water, then immerse it in solution B, and leave it in there until the print’s image first fades and then appears again with a light orange coloration.
Wash again for 10 min. under running water, then place it into the solution C until the grey-black tones come out well. Wash again for 15-20 min. under running water.
There are a multitude of ways to tone cyanotype prints, many formulas that have been edited tell how tone green, pink, lilac, aubergine color and so on… you only have to experiment.
Tags: Cyanotype Toning, Cyanotype toning, cyanotype black toning, brown toning