The chemical solution is yellow before it is exposed to UV light
This week at AEB class, we have been experimenting with cyanotypes. Cyanotypes, invented by Sir John Hershel, are a type of photographic print made using a chemical solution of iron compounds painted onto a surface. The surface is exposed to UV light and then washed, oxidising the solution and creating a blue image. Placing objects onto the painted surface before exposing it will create a print.
Our 1950s vacuum UV exposure unit
#We used an old exposure unit for our prints which allowed us to set a consistent exposure time and intensity. Any source of UV light would work, so the prints can be made by taking them outside to expose them to sunlight. The results of this may be unpredictable due to changes in light levels and ambient temperature. Using the exposure unit could take 15 minutes or less, whereas the exposure time needed in sunlight may be much longer.
The prints need to be placed in a water bath of running water to develop them, and they need to be washed until the yellow tone has completely come out. I found it difficult to judge the timing of this, and on several of my prints I found that the blue tone started to wash away before I took them out. The results widely varied depending on the qualities of the surface I used and density of the application. I found that the best results were achieved using thin, absorbant paper and a medium-thin application of the solution.
Hanging prints to dry
I love the effect of placing feathers directly onto the paper. Unfortunately I lost a lot of the image to fading.
For these prints, I overlayed book pages with negative printouts of my sketches on acetate. I think they would have been more effective as positive images.
I like the effect of the words printed in this image. I might try recreating this with the sketches done in a different way
The linework of my sketches was too thin and so washed off during processing