I prefer to use Sunography paper by Noted Llc which I found produced the best results. The paper has to be exposed for at least 10-15 minutes in bright sunlight and is coated on both sides with light sensitive chemicals.
Here are another selection of Cyanotypes (Sun-prints) this time depicting Stockport college selected from some of my digital photographs. The photographs I chose were transferred onto special inkjet compatible OHP transparencies before being used to create the final images. Some moisture blotted the transparency image creating a watery look to the ‘window’ print which was a bit of serendipity.