here's one I made earlier :: cyanotype

Inspired by a recent exhibition about camera-less photography at the V&A called Shadow Catchers, I thought I’d try my hand at cyanotype, a type of ‘sun printing’.

Cyanotype, originally used for reproducing notes and diagrams in engineering circles (blueprints) was discovered and developed by English scientist and astronomer Sir John Herschel in 1842.

Anna Atkins used the technique to document ferns and other plant life from her extensive seaweed collection. Atkins placed specimens directly onto coated paper, allowing the action of light to create a silhouette effect, and so became the world’s first female photographer.

Using both sun-print paper and sunography fabric, this is the technique I used. Bright sunlight is required, so I kept my fingers crossed, and headed out into the back garden. Both the paper and the fabric come in a black, light-proof bag, so the trick is to keep them in there until you’re absolutely ready to expose them.

For the image at the top of this post, I used a selection of buttons. I had to get the paper out quickly, without exposing any of the other sheets in there to the light (easier said than done!), place it down on a flat surface, arrange the buttons on top of it, and then place a sheet of glass over the top to hold everything in place while it’s being exposed.

After exposing the paper to the sun for two minutes, I whipped it out from under the buttons and glass and popped it back into the black light-proof bag.

And then I tried a few different items…

Then I tried the same thing using the sunography fabric, but because this takes much longer to expose (up to twenty minutes) I only tried one item – the slide film.

With the paper and fabric safely tucked into their respective light-proof bags, I tidied up and came back inside. The paper had to be submerged in cold water for one minute, and the fabric washed under running water for two minutes.

The paper and fabric were coated with a photosensitive solution of potassium ferricyanide and ferric ammonium citrate. On exposure to sunlight, the iron (III) on the parts of the paper or fabric that weren’t hidden by the object placed on top are reduced to iron (II).  The iron (II) then reacts with the ferricyanide to form an insoluble, blue dye (ferric ferrocyanide) known as Prussian blue.

Rinsing with water washes off the (yellow) unreacted iron solution, leaving the Prussian blue print on the areas where the objects weren’t. The areas where objects have protected the paper or fabric from the sun, are left the original colour. Like this…

I suspect you’d have to spend a long time experimenting and learning to produce images of the quality of Anna Atkins‘ or of the artists featured in the V&A Shadow Catchers exhibition, but I did enjoy my first attempt and was quite pleased with the results. I learnt that the flatter the object, the cleaner the image, but some of the less flat objects created prints which almost looked three-dimensional. The fabric was more sensitive and captured the detail within the slide film, as well as some tonal variation.

You may also enjoy:

• here’s one I made earlier :: an explorer of southwold
• here’s one I made earlier :: sketchbooks
• here’s one I made earlier :: the joy of stamps
• here’s one I made earlier :: a nice cup of tea

Further reading for the especially geeky:

• Finished First 6′ Cyanotype Panorama (studioyugen.wordpress.com)
• INSPIRATION: Floris Neusüss & Photograms (artdepartmental.com)
• http://www.creativereview.co.uk/cr-blog/2011/january/shadow-catchers-camera-less-photography (creative review)
• http://www.ameliasmagazine.com/art/shadow-catchers-camera-less-photography-at-the-va/2010/11/09/ (amelia’s magazine)