Traditional Cyanotype – a Process Dating Back to 1842
Most of us are familiar with the traditional cyanotype formula, whose history dates back to 1842. There are several variations, but the basic principle has remained unchanged: two separate solutions, one based on potassium ferricyanide and the other on ferric ammonium citrate.
The two solutions are mixed, usually in equal proportions, immediately before coating the paper.
Formulas of this type have been used successfully for more than a century and a half and will undoubtedly continue to be used for many years. There is good reason for this: traditional cyanotype is relatively easy to prepare and use, requires no complicated processing, and produces durable prints with a characteristic intense blue colour.
Limitations of Traditional Cyanotype
Traditional cyanotype also has some limitations. Among the most important are its relatively high contrast, limited tonal range and rather modest possibilities for manipulating the image during processing.
Another disadvantage is the limited shelf life of one of the stock solutions, together with the need to prepare a fresh working mixture before each coating session.
What Is Single-Solution Cyanotype?
An alternative is single-solution cyanotype. In this approach, the light-sensitive material is prepared using a single working solution, so there is no need to mix two separate components before every use.
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| Cyanotype comparison, photograph by Radosław Brzozowski |
Depending on the formula used, single-solution cyanotype may also offer greater sensitivity, a wider tonal range and slightly lower contrast than the traditional process.
It can also provide greater control over the final appearance of the print through the choice of processing method.