Invented by Sir John Herschel in 1841, Cyanotype, or commonly known as 'sun printing' is an alternative photographic process. It is a printing process that does not use silver gelatin paper and is commonly used in traditional darkroom printing, although you do not need a darkroom to creat them. The Cyanotype is also also known as a blueprint. The characteristic of Cyanotypes is the vivid Prussian blue colour of the print. In the cyanotype printing process, paper or other materials, are coated with a sensitising solution of ferric ammonium citrate and potassium ferricyanide. After drying, the sensitised paper is contact printed with negatives printed on transparencies, or other objects, then placed in the sun or under a UV (Ultra Violet) light source. Once exposed, the image is soaked in water to get rid of surplus sensitizer and to develop the image. This is known as 'dry cyanotype'.
To create some of the images in the gallery, flowers and foliage were placed on watercolour paper, coated with the sensitizer, and exposed whilst still wet. This gives a very different outcome, especially if you add things like a spray or water, lemon juice, vinegar, salt or sprinkles of colour from spices such as turmeric. These are known as 'wet cyanotypes' and are exposed for much longer, sometimes up to 24 hours and beyond, to get the best imagery and detail possible. The great thing about creating cyanotypes using the wet technique is that you never quite know what you are going to get at the end of exposure and developing process. No two images are ever the same, even if you use the same botanicals in an identical design.
Dry Cyanotype Wet Cyanotype