History of cyanotype: Herschel, Atkins and blueprints

Cyanotype was described in 1842 by British scientist and astronomer Sir John Herschel. The process produced stable blue contact prints using iron salts and was cheaper than much early silver photography. Botanist Anna Atkins saw the scientific and visual possibilities almost immediately: from 1843 she used cyanotype photograms to document algae in one of the first books to be illustrated photographically.

John Herschel and the invention in 1842

Herschel investigated light-sensitive iron compounds and introduced the cyanotype process as a method for making and reproducing images. The characteristic color comes from Prussian blue, an iron pigment that forms in the exposed areas of the wearer. The technique did not require expensive silver salts and could be developed with water.

Anna Atkins and Photographs of British Algae

Anna Atkins placed dried algae directly on treated paper and exposed them as a photogram. Her book Photographs of British Algae appeared in parts from 1843. The prints combined scientific accuracy with a recognizable aesthetic: light, fragile plant structures against a deep blue background.

Atkins' work shows why contact is essential. Thin, flat parts become sharp; thicker or raised parts give softer contours. That principle still applies to contemporary botanical prints.

From cyanotype to technical blueprint

The process was later widely used to copy engineering drawings and plans. A transparent drawing could be placed on light-sensitive paper and reproduced in a one-to-one format. From this grew the word “blueprint”, which today also figuratively means a precise plan.

Why artists continued to use cyanotype

Cyanotype has a special tension: the process is simple, but the image can be very refined. The blue color is immediately recognizable, while paper, brush edge, plant shape, negative and lighting make every print unique. Photographers and artists use the technique for photograms, portraits, books, textiles and mixed media.

The chemistry behind the historical process

The classical method uses ferric ammonium citrate and potassium ferricyanide as separate solutions. After mixing, coating and UV exposure, Prussian blue is formed in the fibers during rinsing. Read green vs. brown ferric ammonium citrate for material selection and cyanotype ratios for a practical recipe.

Cyanotype in the twentieth and twenty-first centuries

Although modern copying techniques largely replaced the technical blueprint, cyanotype persisted in art education and alternative photography. Digital image processing gave the process a new entrance: a digital photo can be printed as a large contact negative, after which the final image is created completely analogously with UV and water.

What makes cyanotype relevant today?

• The technique connects photography, drawing, nature study and handicrafts.
• A basic print does not require a darkroom.
• Digital and analogue methods can be combined.
• The process makes material and time visible in the final work.
• Every maker can build their own test library.

Connect yourself to that history

Start with a small botanical photogram on suitable paper. Place one flat sheet under glass or plexiglass, make a test strip and record light and time. The complete beginners guide gives all the steps; the page with 10 cyanotype ideas then helps you choose your own direction.

Frequently asked questions

Was Anna Atkins the inventor of cyanotype?

No. John Herschel introduced the process in 1842. Atkins was an early and influential user who systematically applied cyanotype for botanical documentation.

Why is a technical plan called a blueprint?

For a long time, technical drawings were reproduced as blue prints using cyanotype-like contact processes. The name survived after the technology changed.

Is a modern cyanotype still the same process?

The core—photosensitive iron chemistry, contact exposure, and rinsing with water—is the same. Modern lamps, digital negatives and new carriers expand the possibilities.