Cyanotype is a contact printing technique, which requires UV rays and a negative image of the same size as the final one.
In this printing process, dated from the middle of the 19th century, the sensitive agent is a trivalent iron salt. Trivalent iron salts are the key compounds of other printing techniques such as Platinum, Palladium, and the Van Dyke Brown print. Through the exposure to UV light, the trivalent iron is reduced to bivalent iron, which can reduce other compounds that it comes into contact with.
In the case of Cyanotype the compounds that come into play are: ferric ammonium citrate (the green one) and potassium ferricyanide.
xposure to light forms ferric ferrocyanide (Prussian blue) which stays caught in-between the paper fibers and creates the image. The image we obtain is very stable, but could deteriorate in the presence of alkaline substances. The image could also fade if exposed to an excess of direct sunlight; in this case you can restore it by keeping it in a dark environment for a few days.
Cyanotype prints can be made on whichever surface (fabric, paper, wood).
Sensitized paper can not be stored, it must be used immediately. The drying phase can be accelerated using a hair-dryer on a tepid setting.
The time of exposure varies depending on the UV light’s power and the distance from the paper’s surface.
A 100W light, placed at a 30cm average distance, can use from 30 to 60 minutes time.
There are no developing or fixing phase. A meticulous wash under running water is sufficient to obtain the final print.
The necessary material is easy to find. You don’t even need the safe light; it is enough that you avoid the exposition to the light from energy saving or florescent lamps. These are two types of light which could emit UV radiation. It would be best to work with a press, but as well you may use an equivalent equipment.
To the advantage of the beginner, Cyanotype Kits are available on our website.