If you’ve ever wondered how I make the blue cyanotype prints that saturate my website, have a look at the pictures below.
Whether you’re printing on silk, wood, plaster or paper, all you need are:
1. Chemicals and water,
2. a Surface for printing
3. a Design, and
1. First, mix these powdered chemicals with 100cc of water each:
* Ammonium iron(III) citrate (‘green’ variety) 25g
* Potassium ferricyanide K3[Fe(CN)6] 10g
The chemical names might sound toxic but they’re not – unless you eat them with your lunch.
Supplies are available from Photo Formulary, or just Google “Cyanotype” to find one near you.
2. Paint the silk – or paper, or wood, or whatever you’ve got – with a brush or roller. Avoid brushes with metal surfaces; they’ll react with the iron-based chemicals.
Dry in a dark room.
3. Set up your image in a semi-dark room. Your design could be leaves like this, or a digital negative printed on acetate for photos, or any objects that block light in an interesting way. Take a look at my portfolio for examples.
4. Expose your image outside in direct sunlight. Developing time will vary depending on climate, strength of chemicals, and the objects you use, anywhere from 10-80 minutes. You know the print is finished when it’s darkened to Prussian blue then lightened again.
Final step: Rinse the print for up to 10 minutes. Add some vinegar/citric acid to the rinse water.
Your final impression is the unique combination of light, water, and chemistry of a particular day. Every printing session has unexpected variables depending on your water acidity, the pollution or cloud cover, and where in the world you are.
And most of all, it depends on your creativity.