This is a process in which you get a cyan-blue print. The chemicals used are Ammonium Iron (III) Citrate and Potassium Ferricyanide. The procedure was discovered by Sir John Herschel it was brought to photography by his friends daughter Anna Atkins. The process was used to document the scientific specimen of algae and published in a book.
The process itself, once the right quantities of chemical is made up into the solution needed. It is brushed on to a strong surface that can absorb iron solution like water colour paper and kept in a dark place to dry.
To make an exposure you need to expose it to UV light such as the ones from the sun. These days UV lights can be bought which is a good idea in countries where there is less sunshine. On a nice bright sunny day 10/20 minute exposure is good enough. The UV light reduces the iron in the area that is exposed turning the paper into a grey-ish blue colour. You can use everyday objects to make monograms or you can use large format negatives or lithography film. After the exposure is made the paper is washed in water and the soluble chemical washes away and the insoulble stays leaving the cyan colour. The process was in high use for engerneering prints due to its low cost and fast reproduction. These are what is known as blue prints.
My Cyanotype work:
For my series here I actually made digital black and white negatives of my colour negatives. It is printed on inkjet compatible acetate. I enjoy this process a lot as it is very experimental and I’d love to do more work like this.
You can buy a cyanotype kit from silverprint in waterloo but I habe not tried that yet. It does’t come with a light source so you would have to rely on the lovly sun to come out.
These images are complely out of focus shots of westminister skyline and two of them are also zoomed into during exposure.
Preserving these images is tricky as if exposed to UV light for long they fade. Although strangly if you put them back in the dark they get darker again with time. Its a good idea to not keep it in direct sunlight.