Here is a simple definition of a cyanotype from Wikipedia:
"Cyanotype is a photographic printing process that gives a cyan-blue print. The process was popular in engineering circles well into the 20th century. The simple and low-cost process enabled them to produce large-scale copies of their work, referred to as blueprints."
I think most people recognize the cyan blue color that results. What surprised me was that when you mix the two chemicals involved and paint it on your paper (or fabric), it is a yellow-green color. Below is Mary preparing some fabric.
Once the solution is painted on the surface, it needs to dry (preferably in a dark place). After dry, then you can start placing objects on the surface. It is then exposed to ultraviolet light (we used the sun). Wherever the objects block out the light, the color of the paper or the fabric will remain.
Here is an example. In this picture, you can already see the color changing from the yellow-green to the blue color.
After a short exposure time, you put it in a bath of water to develop. Then you let it dry.
I brought some of my dyed fabric to try. Because this was a gold colored fabric, the cyanotype print comes out more gray green.
Below is an example we did on white fabric.
I had a great time learning something new and we had a really nice afternoon.