April Smith, Ph.D./Executive Director April 30, 2023

Cyanotype is a photographic process using a solution of two different iron-based compounds to create basic images with ultraviolet (UV) light. The cyanotype process was introduced in 1842, and can be used to process images by coating nearly any naturally absorbent material (paper, t-shirts, cards) with the iron solution and letting it dry in the dark before exposure. In this experiment, we are using paper that has already been prepared with the iron solution. It is ready for exposure to whatever interesting items you can find, inside or outside.

You can purchase prepared cyanotype paper to try your own experiments at home using the sun or a UV lamp.

Procedures

  1. Search for interesting items to use on your cyanotype. Flat items will give more detail, while bulkier items will produce shapes and outlines. Try different types of leaves, nails, tweezers, acorns, pine straw, etc. 
  2. Place your chosen items on top of the cyanotype paper in whatever layout you feel is best. Get creative with your designs, but it will work best if the entire design is exposed to the sun or UV light.
  3. Place plastic sheet over the top of your design.
  4. Either place your design in the sun or under a UV lamp for 5-10 minutes. You may need to experiment with time and item placement to see how detailed you can get your design to come out.
  5. Remove the plastic cover and rinse your cyanotype in clean water. Either in a water bath or under a faucet should work.
  6. Let your image dry and enjoy your cyanotype artwork!

Give me the Science!

You’re wondering why this works, aren’t you? Of course you are! Well, the iron compounds used to make cyanotypes are light sensitive, so whatever objects are placed onto the solution-coated paper will block out the UV when the paper is exposed to light. Light exposure oxidizes the chemicals on the paper. Washing removes the chemicals that were not oxidized, and therefore are soluble in water. Everything that was covered by your design will remain white, while everything exposed to light will turn blue.

Here is a great resource that gives much more detail about making your own cyanotypes, but it also provides a little insight into the scientific process involved. Our procedures above make cyanotypes easy for all ages and abilities to enjoy: https://www.alternativephotography.com/cyanotype-classic-process/