Cyanotype printing, also known as sun printing, is a technique which was discovered in 1842 by scientist Sir John Herschel. At the time, it was used primarily to reproduce engineering and architectural drawings. When the botanist Anna Atkins learned of the process, she used it to document plant life from her collection, and is credited with bringing the process to the world of photography.
The process is fairly simple. Chemically treated surfaces like paper and fabric are exposed to sunlight, a chemical reaction takes place, and you’re left with fascinating silhouettes on beautiful blue backgrounds. While this normally requires mixing chemicals, pre-treated papers are available, making it easy and safe to involve children.
- light sensitive paper
- objects with interesting shapes and details to print e.g. flowers, ferns, keys, paper clips, transparencies of photographs or drawings, lace
- a piece of clear glass or plexiglass to hold objects in place
- a very sunny day
1. To make cyanotypes the easy way, you’ll need light sensitive paper which is sold in packages with instructions. There are a number of different brands like Sunprints and Sunography, which I used and purchased at The Paper Place. Another option in Toronto is Efston Science. I was unable to find it in art supply stores or photography shops, but was told museum gift shops often carry them.
2. Begin by selecting items you would like to use. Consider ones that will make interesting images when light shines through them. Arrange objects on a regular sheet of paper to determine how you would like them to look.
Once ready, uncover a sheet of light sensitive paper, lay it down on a flat surface away from the sun, and arrange the objects on top. Cover with a piece of clean glass or plexiglass to hold everything in place. This is helpful when using objects like feathers and leaves because it ensures light will not get underneath the edges, so images will appear sharp.
Place in bright sunlight for the length of time instructed. Ours were kept in the sun for 15 minutes, but this may vary based on the paper you buy.
3. Remove the objects and gently rinse the paper under cold water for several minutes, until the water runs clear. Your print will magically appear, revealing shapes on a beautiful indigo blue background.
Tip: If using feathers, avoid white ones. Our feathers showed up beautifully except for the white one. It seems the sun can penetrate easily through a white feather, but not coloured ones.
Here’s the science behind it:
The paper is coated with 2 chemicals called potassium ferricyanide and ferric ammonium citrate. Once exposed to a source of ultraviolet light, such as sunlight, a chemical reaction occurs forming ferric ferrocyanide, a blue dye known as Prussian blue. When objects are placed on treated surfaces, they block the sunlight from reaching the paper in those areas, so they remain white. Exposed areas will turn blue.
My daughter ended up framing her cyanotypes, which turned out beautifully!