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In focus

From 'actino-chemistry' to 'photo-graphy': photographic experimentation in the letters of Sir John Herschel

by Carolin Lange

Tracing early experimental practices, Carolin Lange from the Photographic History Research Centre, De Montfort University Leicester, explores the vast network of individuals curious about photography, through the letters of Sir John Herschel.

From the official announcement of the photographic process in 1839 by Louis Daguerre, many experimental scientists and other potential practitioners expressed curiosity about this new field. Sir John Herschel, one of the key figures in nineteenth-century science, was central to the discussions on the processes and results of photography. Most famously, his correspondence with William Henry Fox Talbot resulted in the fixing agent for silver-based photography.

Less known is that between 1839 to 1845, Herschel reported his photographic research to regular correspondents such as William Whewell, John William Lubbock, George Biddell Airy, James David Forbes, Robert Hunt, Hans Christian Ørsted and John William Draper. Some expositions were very detailed, others were more of a side note. In any case, they are characterised by his excitement for this new field. Herschel quickly realised its potential as a new branch of science, which he called 'actino-chemistry': the study of the nature of light through photochemical reactions.

Many of Herschel's experiments explored volatile-coloured effects when a photographic substance was exposed to the solar spectrum. ‘There is no end of the strange photographic results’, Herschel reported to Whewell in January 1840. A month later, Herschel communicated these "strange results" to the Royal Society including detailed drawings of his spectral photographs.

Herschel aimed to understand the interaction of light and matter through ephemeral photographic results and direct observations. In a letter to Forbes, he discussed the 19th-century theory of light, which posited that it was composed of three elements: visible light, heat, and a 'chemical action' of light. He translated their maximum effects into representative curves. To Lubbock, he reconciled visual and photographic impressions by translating them into a comparative pencil drawing.

Early experiments resulted in various types of photographic objects, such as spectral photographs, contact prints, photograms, and camera-based images. Although Herschel worked with cameras as early as 1839, he devoted his photographic output almost entirely to photographic spectra and contact prints. While a few of Herschel's contact prints have survived in the archives, far fewer of his spectral photographs have, most notably as the appendix to his communication in the 1842 Philosophical Transactions.

Herschel's 1842 paper explored the photographic properties of light exhibited by botanical colours. Only one scientist repeated and extended this set of experiments: Mary Somerville. Herschel's correspondence shows that after a visit to Collingwood in Kent in the autumn of 1844, Somerville had all the knowledge and instruments she needed to conduct her own experiments on the subject. A year later, she sent Herschel a description of her experiments with botanical colours, which she had carried out in the summer of 1845. Herschel communicated her experiments to the Royal Society, and they were published in the 1846 Philosophical Transactions. As with Herschel's botanical spectra, none of Somerville's spectral photographs seem to have survived in the archives, leaving us only with her careful drawings.

Herschel received many letters reporting new developments in photography. In 1844, for example, he was approached by Hans Thøger Winther, a Norwegian pioneer of photography, who hoped that by writing to Herschel he could gain greater exposure within British networks. This hope was not far-fetched. Herschel was known for encouraging knowledge-sharing and discourse. In a letter to J. E. Bidwell, Herschel articulated his position on photographic patents:

In short, Photography as an act is in my opinion perfectly open - unpatentable (however particular processes of it maybe so) and likely [...] to receive great accessions of power and interest- and that speedily.

As photography matured, many more scientists and photographers shared their work with Herschel, sending him photographs. Naturally, he was one of the first people to receive what is now regarded as the first photobook: Photographs of British algae: cyanotype impressions by Anna Atkins, Herschel's collection also included photographs by family relative John Stewart, and scientist and photographer Henri Victor Regnault. Warren de la Rue, a pioneer of astronomical photography, also regularly updated Herschel on his research by sending him lunar and solar photographs. By the 1870s, Herschel's photographic collection was a record of its widespread application.

Anna Atkins, 1843, Photographs of British algae: cyanotype impressions. RCN 9352, The Royal Society. Sir John Herschel's own volumes are held by the New York Public library.

Tree study and sunny glade, photograph by John Stewart and Victor Henri Regnault. 20.5 x 26.7cm. 1853. MS/784/4. The Royal Society.

Photograph of sunspots by Warren de la Rue, 1864. MS/312, The Royal Society.

In addition to keeping his collection of photographs in the library at Collingwood in Kent, Herschel conducted his own photographic experiments there. These are recalled in the draft of a letter to Dominique François Jean Arago from 1848, written on a cyanotype photogram and coloured paper with botanical tints. The reuse of a photographic specimen to scrawl a dispatch suggests that such papers were common enough.

A short biography of Sir John F.W. Herschel by his youngest daughter, Constance Lubbock, indicates that the infrastructure for photography and its scientific experimentation was also accessible to the children. Later in life, several of Sir John Herschel’s children used photography as part of their professional work. Sir William James Herschel utilised photography in his experiments on fingerprinting patterns to enlarge and analyse the prints and Julia Herschel used her father's cyanotype process to illustrate her handbook of Greek lace making.

The family's collective effort to preserve Sir John Herschel's extensive correspondence has resulted in a key record for understanding his role in the production of knowledge in the nineteenth century. The letters also demonstrate his role in the intertwined practices of professional inventors and curious amateurs of photography, with Sir John Herschel at the centre of the dissemination of a key technology of the period.

About the author:

Carolin Lange is an artist specializing in experimental photography and spectroscopy of the 19th century. She is currently a Midlands-4-Cities funded PhD candidate at the Photographic History Research Centre at De Montfort University, Leicester. As part of her PhD, she undertook a placement at the Royal Society in 2023 on the 'Herschel Letters' digitisation project.


Constance A. Lubbock. 1938. A Short Biography of Sir John F.W. Herschel. Cambridge: Privatdruck.

Hentschel, Klaus. 2002. Mapping the Spectrum: Techniques of Visual Representation in Research and Teaching. Oxford; New York: Oxford University Press.

Millman, Peter Mackenzie. 1980. ‘The Herschel Dynasty; Part I: William Herschel; Part II: John Herschel; Part III: Alexander Stewart Herschel.’ Reprinted from Journal of the Royal Astronomical Society of Canada, 74(3-4-5), 1980, 134-146; 203-215; 279-290.

Moore, Keith. 2008. ‘Photographs by the French Scientist Henri Victor Regnault’. Notes and Records of the Royal Society 62 (4): 409–13.;

Schaaf, Larry. 1979. ‘Sir John Herschel’s 1839 Royal Society Paper on Photography’. History of Photography 3 (1): 47–60.

Schaaf, Larry J. 1992. Out of the Shadows: Herschel, Talbot & the Invention of Photography. New Haven: Yale University Press.

Wilder, Kelley. 2024. ‘Photology, Photography, and Actinochemistry: The Photographic Work of John Herschel’. In The Cambridge Companion to John Herschel, edited by Stephen Case and Lukas M. Verburgt, 1st ed., 160–85. Cambridge University Press.;

Wilder, Kelley, and Martin Kemp. 2002. ‘Proof Positive in Sir John Herschel’s Concept of Photography’. History of Photography 26 (4): 358–66.;