Cyanotype

Cyanotype is a photographic printing process that gives a cyan-blue print. The process was popular in engineering circles well into the 20th century. The simple and low-cost process enabled them to produce large-scale copies of their work, referred to as blueprints. Two chemicals are used in the process:

• Ammonium iron(III) citrate
• Potassium ferricyanide

These chemicals are mixed to a 1:1 ratio. While researching online I found the following process to be the most commonly used, this involved.

• Mixing the two chemicals (1:1)
• Using just enough of the mixture to cover the area or sheet of paper and leave to dry.
• Apply an image printed on to acetate.
• Place both on to a UV light box.
• Apply a cover over the paper and image and weight/clamp it down on to the surface of the light box.
• Expose the image (in this case for 6-8 minutes)
• Remove the acetate image and place the paper in to water
• The areas of the image will turn bright blue.
• Remove the image and place it in to another bowl of water with a drop of peroxide to fix the image to stop the process.
• Leave to dry.

This process is to be done a a dull light or dark room as the chemical will react to the light. I believe this process could be done using negatives from a film camera, but using paper coated with the mixture instead of photographic paper. Below I have inserted the video demonstration I first watched, I beleive it to be the most helpful and explanatory. I look forward to trying this process in teh near future.