The cyanotype process was invented by Herschel in 1842, mainly as a means to reproduce notes and diagrams. The process was published as a last minute addition to another larger paper he had written. Herschel came across the process while experimenting and corresponding with a friend, Alfred Smee, a chemical correspondent to the Bank of England who had taken some interest in photography. Originally not very successful because of the limited tonal range and Prussion blue color, the process did not really become as popular until its success in the 20th century.
The process made Anna Atkins somewhat famous and gives her the title as the first female photographer when she used the process to photograph a series of British seaweeds, compiling them into a book entitled British Algae.
The coating solution is made up of two separate solutions which are mixed
together before coating the material. Solution A is made up of 25 grams of Ferric ammonium citrate and 100mL of water. Solution B is 10grams of Potassium ferricyanade and 100mL of wawater. Equal quantities of each solution are then mixed together in a third container, but need to be used with about a half hour because the solution does not last very long once mixed.
After evenly coating the paper and allowing it to dry, a negative can be placed over the paper and both should be exposed to UV, light generally natural sunlight. Depending on cloud coverage, number of coats, and the density of the negative, the exposure can take from a few minutes up to an hour. The paper should be exposed until the image looks as if it is getting lighter instead of darker and the blue is starting to fade. This is one of the longer process for exposure.
Fixing the image is as simple as running water of the paper for several minutes until the residual chemicals are removed. This simple fixing method that does not require the use of hypo is another reason for the popularity of the cyanotype.
The cyanotype "became the most commercially successful of all of Herschel's processes; indeed, it is the only process from the first decade of photography to survive in active use well into the twentieth century..." Mostly used for acrchitectural blueprinting, the cyanotype process has become a craft project and exciting way for amateur image makers and everyday creative persons to express themselves using such a cheap and simple method. Cyanotype fabrics with the high contrast of white shapes over the deep blue are a stunning way to transform fabric into a work of art. This set of chair seats and pillow cases is an example of such innovation.
My experience:
After preparing solutions A and B and mixing the two together in a separate container, 100% rag paper was coated with the green colored solution and then allowed to dry. We then applied a second coat and also let it dry.
I had two different negatives so both images were brought outside with the negative ink side facing the coated side of the paper. It was a very sunny day, but the cyanotypes still take a long time to expose so we were outside for about 20 minutes until the blue of the images started to fade.
The images were then fixed by running them under water for about five minutes. I left one image just as was, with only the water fixative:
For the other print, and two strips that i cut off of it, I used the other three toning solutions. The first was soaked in a mixture of tea and water, which was supposed to produce a darker blue effect. The strip I put in that solution was already pretty dark blue so it did not really have much of an effect.
I soaked the actual print in the tea solution first, and the strong bleach solution which resulted in a brownish tone, but I did not really like the final result.
The other strip was soaked in the weak ammonia first, and then in the tea solution. This was supposed to result in a blue-yellow tone, but I did not really achieve that result and instead ended up with a faded blue color.
2nd toner, 3rd toner, 1st toner.
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