Blog #3

The Cyanotype process is a photographic technique where a paper is sensitized in the dark (away from Ultra Violet Light) with a photo-sensitive emulsion. This emulsion is made up of two parts; part A being Potassium Ferricyanide mixed with distilled water and part B being Ferric Ammonium Citrate (green) mixed with distilled water. Part A and Part B are combined just before sensitizing the paper in order to maintain a long shelf life when the two parts are not in use. Once the sensitized paper is dry, it can be exposed to sunlight light and then thoroughly washed with regular water. Whatever bit of paper that was exposed to light will become blue, and any paper that was not exposed to light will remain white.

This process was first introduced by an astronomer, chemist and mathematician named Sir John Frederick William Herschel around 1820 during his experimentation with Hyposulphite of soda, silver, and salts. Herschel was born in 1792 of British courtier Mary Pitt and astronomer William Herschel (who discovered the planet Uranus). Around 1816, John Herschel’s father William was slowing down and became unable to further his studies. Thus, John decided to move back home and take up his father’s work observing the night sky with his father’s 40ft telescope. Considering the amount of note taking necessary to account for the infinite number of objects in space, Herschel required a method to copy and fix his notes to new pieces of paper. Between 1819 and 1821, John Herschel discovered through experimentation that Hyposulphite of soda dissolved silver salts. In doing so, Herschel had unknowingly uncovered a method for fixing an image onto a paper medium permanently, which happened to be the downfall for many image makers prior. It was not until 1839 that Herschel would actually begin to test his chemical findings with the addition of light and truly start his profound journey into the beginnings of ‘fixed image’ photography. It was then (1839) that Herschel read over a letter that his friend wrote to his wife promoting the experiments of Louis Jacque Mande Daguerre with the ‘actions of light’. Louis Daguerre worked closely with Nicephore Niepce on developing the Daguerreotype and published the details to create these images in 1839. Daguerre’s own findings struck John Herschel’s interest and he began experimenting with creating his own images. Between 1839 and 1842, Herschel began publishing papers on photographic processes. One of his most important papers was titled On the Art of Photography; or the Application of the Chemical Rays of Light to the Purpose of Pictorial Presentation and was read to the Royal Society on March 14^th, 1839. In this paper, John Herschel coined the terms negative, positive, emulsion and photography (photography from the Greek roots “light” and “writing”) and made this information free to all without patenting or claiming ownership of the methods discussed, similar to Niepce and Daguerre. Often times the Daguerreotype receives all of the credit for the beginnings of photography, but it was John Herschel who discovered the chemical method used to permanently fix an image, allowing the result to last forever.

In its early years, the Cyanotype process consisted of coating paper with Iron Salts, contact printing an image, and then washing the print with water. (thanks to Herschel) This process was not commercially used until Anna Atkins began creating contact prints of plants and flowers in 1843 and published the first book photographically constructed with Cyanotypes titled British Algae: Cyanotype Impressions. 

John Herschal's 'Lady with Harp' cyanotype

Anna Atkins 'Asplenium Marinium'

Anna Atkins' Cyanotype Book Cover

References:

http://iphf.org/inductees/sir-john-frederick-william-herschel/

http://www.alternativephotography.com/cyanotype-history-john-herschels-invention/

http://www.alternativephotography.com/cyanotype-classic-process/