- Film negatives (preferably medium format or larger)
- Watercolor paper
- Potassium ferricyanide
- Ferric ammonium citrate
- 2 light-protective bottles (the darker in color, the better)
- Small mixing cup
- Protective gloves
- Paintbrush or sponge brush
- Plastic tray
- Hydrogen peroxide (optional)
- Safe light (preferred, but not necessary)
How to Make a Cyanotype. The cyanotype was born in 1842 and is still seen today. The brilliant blue color and natural timelessness of cyanotypes make them a favorite among those who enjoy alternative photography processes. Best of all, it's a fairly straightforward process that only requires safe-to-handle chemicals. No fancy photo lab equipment is necessary. These are the basic instructions for making a cyanotype.
Set up a workspace for treating the watercolor paper. A dark room lit with a safe light is ideal. In any event, the room should be as dim as possible and away from direct sunlight.
Put on the safety gloves, and proceed with mixing the chemical solutions. A common recipe calls for 25g ferric ammonium citrate and 100ml water in one bottle, 10g potassium ferricyanide and 100ml of water in the other bottle. Mix until the chemicals are fully dissolved. Important note: the 2 chemical solutions need to remain separate until the paper is to be treated.
Place equal amounts of the 2 chemical solutions into the mixing cup. Cyanotype chemicals are short-lived once mixed together, so mix only what you think you will need for your project. You can always mix a little more, but unused cyanotype mixture must be discarded.
Paint the chemical mixture onto the surface of the watercolor paper using the sponge or paintbrush. To avoid wasting chemicals, treat only the part of the paper where the negatives will be placed.
Allow the treated paper to dry thoroughly in a dark area. It is important to keep the treated paper out of light until it is time for printing.
Place the negative(s) on the treated paper in the darkened room. Consider placing the negative and paper in a secure-backed picture frame to hold the negative in place. Once everything is in place, cover with a light-protective cloth and carry outside.
Place the negative and paper in direct sunlight for about 10 to 15 minutes (denser negatives might take longer).
Once the paper has been exposed, bring inside and place it into the plastic tray. Allow it to sit under running water for about 5 minutes.
Pour a cap-full of hydrogen peroxide into the water wash to get a quick preview of what your final image will look like.
Allow cyanotype to dry completely.
It can be tricky getting the chemicals mixed just right. Some formulary sites actually offer bottles of pre-mixed cyanotype chemicals, which removes the guesswork and leaves more time for the fun stuff. Cyanotypes can also be printed on other fibrous surfaces such as cloth.