Historical Processes: The Cyanotype


In the grayscale days of early photography, the cyanotype was a splash of electric blue. Today, this alternative process continues to attract the curious and experimental, seduced by its simple development and distinct aesthetic. The origin of the cyanotype dates to the formative years of photography and one of the medium’s most important—if underappreciated—contributors, Sir John Herschel. Despite being cast in the shadows of Daguerre and Talbot, Herschel was one of the most important scientists experimenting with photochemistry at the time. Talbot, for example, owed the permanence of his calotype process to Herschel’s discovery that hyposulfite of soda acts as a solvent of silver nitrate. And it is in Herschel’s writings that we find the first use of the words photography, emulsion, positive, and negative. While his contemporaries were content to focus on silver-based processes, Herschel’s interests were more universal. The cyanotype serves as just one testament to his exhaustive investigations into photosensitive compounds.

Figure 1. Sir John Herschel

The light sensitivity of iron salts had been known since the experiments of Count Bestuscheff in the early 18th century. Prussian blue, the distinguishing color of cyanotypes, was first used in oil and watercolor pigments as a stable and affordable means of producing rich blue tones via the oxidation of ferrous ferricyanide salts. In 1842, Herschel outlined the photographic application of this reaction to the Royal Society of London in a paper discussing a variety of photosensitive compounds.

Compared to the daguerreotype and salted paper print, cyanotypes are much simpler to make. First, paper is coated with a solution of iron (III) salt and potassium ferricyanide under low light. Once dried (in the dark), an object or negative is contact-printed on the treated paper and placed in the sun. Development begins by submerging the paper in water. Areas that have been exposed to light turn blue while unexposed regions wash clear. Oxidation completes during the drying process, revealing the vibrant blues that characterize the medium.

Figure 2. Anna Atkins, Photographs of British Algae: Cyanotype…
Figure 3. Anna Atkins, Zygnema nitidum, from Photographs of British…

The most famous early adopter of the cyanotype was the English botanist Anna Atkins. Daughter of esteemed entomologist and chemist John George Children, Atkins received a scientific education, even illustrating some of her father’s texts. Family friends with both Talbot and Herschel, Atkins was privy to the latest photographic advances and, in 1843, she began creating cyanotypes as illustrations to supplement William Harvey’s Manual of British Algae. Working over the next decade, Atkins carefully composed and labeled hundreds of cyanotypes of specimens for the project. The end product serves as the earliest publication of a photobook: Photographs of British Algae: Cyanotype Impressions.

Figure 4. Anna Atkins, Rivularia nitida, from Photographs of British…
Figure 5. Anna Atkins, Gelidium rostratum, from Photographs of British…

In her introduction, Atkins explains the logic behind using Herschel’s invention for her herculean endeavor: “The difficulty of making accurate drawings of objects as minute as many of the Algae and Conferva has induced me to avail myself of Sir John Herschel's beautiful process of Cyanotype, to obtain impressions of the plants themselves.” Atkins’s emphasis on the speed and accuracy of the process continues to resonate in discussions of scientific photography today. Atkins published Photographs of British Algae in several volumes. About a dozen extant copies remain, including one Atkins gifted to Herschel, currently housed in the New York Public Library.

Figure 6. Amateur Snapshot Album, 1890-2

In the 19th century, the cyanotype was primarily adopted not for its striking color but for its practical applications. The stability and affordability of the process made it a popular choice for printing snapshots, proofing negatives, and preserving archives. It also provided the mechanism used for creating early blueprints by architects and engineers.

Figure 7. Plans of Tracks Under Union Square, c. 1891

The cyanotype was resurrected by experimental and niche photographers in the mid-20th century and appears in the contemporary work of Adam Fuss, Christian Marclay, and Meghann Riepenhoff, among others. At the same time, the minimal technical knowledge needed to create viable cyanotypes has made them popular first steps into the world of analogue photography. Today, you are as likely to run into a cyanotype in an art gallery as you are a science museum.

Figure 8. Cyanotype Paper

There are a number of options available for photographers interested in creating cyanotypes. Photographer’s Formulary makes a Liquid Cyanotype Printing Kit that allows you to sensitize a variety of surfaces for creative applications. In 1994, British photographer Mike Ware developed a variation of the cyanotype using ammonium ferric oxalate and ammonium ferricyanide to increase stability and sensitivity that has been dubbed the “new” cyanotype. His process can be found in Photographer’s Formulary’s New Cyanotype Kit. If you don’t want to deal with sensitizing your own materials, Cyanotype Store makes paper and cotton squares that are pre-sensitized and ready for use.

Have you made cyanotypes? What is your favorite subject for this beautiful process?

To read about more great classic cameras, click here.