The Cyanotype - Photographic Processes Series - Chapter 4 of 12

Summary

Origin

Sir John Herschel, an English astronomer and scientist, developed the cyanotype around the time William Henry Fox Talbot was working on photography. The process emerged after photography had been announced by Daguerre and Talbot. Herschel also helped Talbot investigate ways to make photographic images permanent.

Process and distinctive qualities

Cyanotype is a non-silver photographic process that uses iron salts to create a permanent image in vivid blue and white.

The basic process is:

1. Combine potassium ferrocyanide and ferric ammonium citrate.
2. Brush the mixture onto paper and let it dry.
3. Place a negative in contact with the prepared paper and expose it to sunlight. The paper changes color where light reaches it.
4. Rinse the exposed paper in plain water to bring out the bright blue image.

The image can be seen during exposure, giving the process “printing-out” qualities. Washing also brings out its strong blue appearance, which has a latent-image quality.

Early and later uses

Cyanotype saw limited use in the 1840s, including for botanical records. Anna Atkins, the daughter of one of Herschel’s friends, placed botanical specimens on prepared paper to make images without drawing them. She published several series of these works, described in the subtitles as the first photographically illustrated publications.

The process later became widely associated with engineering drawings and plans, which became known as blueprints. Cyanotypes were also made inexpensively from gelatin-silver negatives, including as test prints and contact sheets.

Makers and visual character

Many surviving cyanotypes were made by amateurs. The subtitles note that college students in the 1880s and 1890s were particularly common makers. The process’s intense blue color gives the images a distinctive visual character.

Speakers and sources featured

• Speaker: The subtitles do not identify the speaker or speakers by name; the content is presented as an unnamed narration or interview.
• Historical figures discussed: Sir John Herschel, William Henry Fox Talbot, Daguerre, and Anna Atkins.