The Cyanotype process uses Iron compounds to set images as opposed to Silver Halides used in conventional film photography. The basic cyanotype recipe has not changed very much since Sir John Herschel introduced it in 1842. However, some advances have been made by Mike Ware in what is referred to as the New cyanotype process. Ware’s cyanotype formula has less bleed, shorter exposure times and a longer density range than Herschel’s, but it is also slightly more complicated to mix and uses more toxic chemicals.
Prints can be made either as photograms or using a negative the basic process is the same.
The cyanotype process is simple. It can be done easily in a few steps:
The cyanotype is made up of two simple solutions.
- 10 gms in of Potassium ferricyanide 100ml water.
- 25 gms of Ferric ammonium citrate (green) in 100ml water.
- The two solutions are then blended together in equal parts.
Preparing the canvas
- Paper, card, textiles or any other naturally absorbent material is coated with the solution and dried in the dark.
Printing the cyanotype
- Objects or negatives are placed on the material to make a print. The cyanotype is printed using UV light, such as the sun, a light box or a UV lamp.
Processing and drying
- After exposure the material is processed by simply rinsing it in water. A white print emerges on a blue background.
- The final print is dried and admired.