Cyanotype photography, also known as sun printing or blueprinting, is a photographic printing process that produces a cyan-blue image. It involves coating paper with a light-sensitive solution, placing an object or negative on it, exposing it to UV light, and then washing it to reveal the image. Examples include botanical prints, contact prints, and images created using digital negatives and objects

Traditional cyanotype is a camera-less photographic process that produces beautiful Prussian blue prints. This process was discovered by Sir John Hercshel in 1842, and was used as a means of reproducing drawing s and diagrams (blueprints).

In the mid-nineteenth century, artist and botanist, Anna Atkins brought the process to the attention and imagination of the public when she produced a series of cyanotype prints of seaweeds. She placed the algae specimens directly on to photosensitised paper creating a silhouette effect, known as a photogram.

The process involves mixing two chemicals: potassium ferricyanide and ammonium citrate to create a photosensitive solution. This is then applied straight after mixing to an absorbent surface (paper, fabric, bone, leather, shell, etc.) after which it is left in a dark place to dry. Allowing light to reach the paper during the drying process will spoil the print. The paper (or substrate) can then be stored in a lightproof container or bag before use.

Prints can then be made by placing a negative (object or a photographic negative) on to the surface and exposing the coated surface to sunlight or an ultraviolet lamp. Results ae usually obtained after about 10-20 mins, though this can vary considerably due to the strength of the sun and the surface being used to create the print. It’s best to create a test piece prior to exposure to ensure you get the results you want.