Cyanotype is a photographic printmaking technique that can be used to hand print designs onto fabric and paper. You may have heard of this method in a photography class, or you may be familiar with the blue sunprints or natureprints papers for kids – this is actually the same process. However instead of buying pretreated paper, you can buy the cyanotype sensitizer yourself and print on any fabric of your choice! The process is inexpensive, very simple to get started and relatively low-toxic, making it a great printing method for crafters and artists alike.
With cyanotype printing your chosen artwork is essentially printed onto the fabric in a dark blue dye that is very permanent. Since the image is printed in a dye and not an ink, the texture of the fabric is not changed and you can print on fuzzy fabrics such as corduroy, felt and velvet.
The cyanotype print is always dark blue to start with, but this blue image can be varied by printing onto different colors of fabric and different textures, or through a process called toning that transforms the blue to brown, black, yellow, etc.
Invented by John Herschel in 1842, the cyanotype image is formed when paper or fabric that has been coated with the sensitizing solution is exposed to UV light. Where the light penetrates to the sensitized surface a dark blue dye is formed, and where it is blocked, nothing is printed. So you can use something like an old-fashioned black-and-white negative to form an image, or just interesting shapes like leaves and paper cut-outs. The dye that is formed is called Prussian blue and is very permanent and water insoluble, giving a long-lasting print.