According to my research, it was Sir John Herschel who discovered the anthotype process and not Mrs Mary Somerville. As soon as I publish an article or text mentioning “Anthotype” and “Herschel”, I invariably get comments saying that it was Mrs Mary Somerville who “invented” the anthotype process. I have not seen any evidence of this in my research and share my findings here in chronological order.
It would be very nice to be able to credit Mrs Mary Somerville for having discovered anthotypes. Those of you who know me know I am an avid admirer of Anna Atkins and the heroic work she did printing cyanotypes (a process introduced to her by Sir John Herschel, a family friend). It would be great to even out the ratio between female and male scientists. The truth is that none of my research suggests Mrs Mary Somerville had any part in the discovery of the anthotype process. She shared her research with Sir John Herschel, which he subsequently published in a letter, crediting her; but that was 6 years after Sir John Herschel first publicly mentioned his findings on anthotypes. For those of you who believe that it was Somerville who discovered the process, please send the references and sources to me at firstname.lastname@example.org or in the comment below; I would be happy to revise my research.
The sources on the Internet crediting Mrs Mary Somerville with the discovery of the anthotype often state “… in 1842, Mrs Mary Somerville discovered anthotypes and sent her findings to Sir John Herschel, who published her research…”. According to records, the letter was published, but the date is incorrect. The letter containing Mrs Mary Somerville’s research was published in 1845, not 1842 and Herschel had done extensive research on the anthotype documented as early as 1839. Herschel’s anthotypes from this time can be seen at the Harry Ransom Centre. Herschel refers to an experiment with the anthotype process on October 11, 1839 in a paper published at the Royal Society of London. Herschel properly introduces the anthotype process, with detailed accounts of experiments and observations, in a paper from 1842, still many years before Mrs Mary Somerville’s research and letter.
In 2008, I started researching the history of Anthotypes when writing the book Anthotypes – Explore the darkroom in your garden and make photographs using plants. I did extensive research and dug out any historical document I could find in online sources such as The Royal Society of London, as well as spending a few weeks sitting in the Royal Library. (Sometimes with a pram and a sleeping baby next to me—always with white cotton reading gloves on so as not to damage the documents and books!). My anthotype book was published in 2012 and includes a section on the history of anthotypes, stating all the above facts. The history is also freely available to read here.
I believe I have covered most sources, but I would gladly look into more if anyone has a secret stash of historical papers somewhere. I listed all the references in a timeline below, if anyone gets inspired to dig deep and do research on their own. This will hopefully shed some light on the discovery of the anthotype.
Henri August Vogel discovered that plant juices are sensitive to light.
Vogel experimented with making emulsions from violets and poppies and found them to be photosensitive. The experiments are described in Schweigger’s Journal (1813, IX, 236). He writes:
“An alcoholic tincture of red carnations turned white in a few days behind blue glass, while behind red glass it was still purple after about the same length of time. Cotton and paper colored with this tincture showed the same differences. The petals of a corn poppy (Papaver rhoeas), mounted behind a blue glass, turned whitish after a few days; behind a red glass the color remained unchanged.”
Josef Maria Eder, History of Photography, published by Dover Publications, Inc. New York, 1945
Theodor Freiherr von Grotthuss discovered that the absorbed light rays are active in the production of chemical changes
Grotthuss set a basic law of science, called “Grotthuss law of photochemical absorption”, in 1817 after discovering that “only the absorbed light rays are active in the production of chemical changes”.
David Volman One Hundred Years of Photochemistry, published by the Department of Chemistry, University of California
Michel Eugène Chevreul does important research on colour contrast
Chevreul carried out several experiments in the art of dyeing and studied the changes and permanence of dyes on fabric made by water, air, sun and heat. He also investigated how oxygen in the air and moisture affect the decomposition of colours when they are exposed to light. He published his findings and research on colour contrast in 1839 in French, though, according to S.D. Humphrey in his book A System of Photography, Chevreul was important but did not discover the anthotype process:
“The influence of light upon the growth and germination of plants is very curious and interesting. The facts connected with this subject have been investigated by Mr. Chevreul, Mr. Hunt and Sir John Herschel. To the latter gentlemen we are indebted for the enquiries which have led to the publication of the Anthotype process.”
Michel Eugène Chevreul De la loi du contraste simultané des couleurs published in 1839 in French by Imprimerie Nationale, Paris
Michel Eugène Chevreul The Principles of Harmony and Contrast of Colours, and Their Applications to the Arts: Including Painting, Interior Decoration, Tapestries, Carpets, Mosaics, Coloured Glazing, Paper-staining, Calico-printing, Letterpress Printing, Map-colouring, Dress, Landscape and Flower Gardening, Etc, published in 1854 in English by Bell and Daldy, London
S.D. Humphrey. A System of Photography, second edition, published in 1849 by Albany
Herschel starts experimenting with anthotypes
Herschel makes a reference to an experiment on October 11, 1839 in the paper published in 1840 to the Philosophical Transactions of the Royal Society of London (On the Chemical Action of the Rays of the Solar Spectrum on Preparations of Silver and other Substances, both metallic and non-metallic, and on some Photographic Processes). This is perhaps the first mention of the anthotype process:
Though regarding the process too slow, Herschel writes:
“We all know that colours of vegetable origin are usually considered to be destroyed and whitened by the continued action of light. The process, however, is too slow to be made the subject of any satisfactory series of experiments; and, in consequence, this subject, so interesting to the painter, the dyer and the general artist, has been allowed to remain uninvestigated.”
But, he continues:
“It appeared therefore to merit inquiry…” and “The want of sunshine has alone prevented me from pushing these inquiries to the extent to which, it will appear from the result of the only trials I have made, they well deserve to be pursued.”
Herschel then describes his experiments and observations; an experiment he describes is dated October 11, 1839:
“A paper so tinged (No. 599.), of a very fine and full blue colour, was exposed to the solar spectrum concentrated, as usual, (October 11, 1839), by a prism and lens; a water-prism, however, was used in this experiment, to command as large an area of sunbeam as possible.”
Sir John F.W. Herschel, ‘On the Chemical Action of the Rays of the Solar Spectrum on Preparations of Silver and other Substances, both metallic and non-metallic, and on some Photographic Processes’, Philosophical Transactions of the Royal Society of London, 1840, 131, 1-59.
Herschel properly introduces his discovery of the anthotype in a paper to the Philosophical Transactions of the Royal Society
The paper disclosed the anthotype process and the effects the sun has on paper coated with flower and plant juices. Herschel found that heat, as well as light and moisture, had an effect on the pigments, and writes:
“The discharge of colour from blued guaiacum by mere heat, has been shown above (Art. 156.) to take place at a much lower temperature in the presence of moisture than when dry…”
Herschel describes in detail his experiments and observations of the action of different colour rays in the spectrum, gives examples of experiments with flowers as well as turmeric, and the effect of substances such as chlorine and soda.
Sir John F.W. Herschel, ‘On the Action of the Rays of the Solar Spectrum on Vegetable Colours, and on some new Photographic Processes’, Philosophical Transactions of the Royal Society of London, 1842, 132, 181-215.
George Thomas Fisher Jun. credits the discovery of the anthotype process to Sir John Herschel in the book Photogenic Manipulation:
“The expressed juice, alcoholic, or watery infusion of flowers or vegetable substances, may be made the media of photogenic action, and the discovery of these interesting faces are, as in the former case, due to Sir John Herschel.” However, he goes on to dismiss it as “in a practical point of view almost useless”.
George Thomas Fisher Jun. Photogenic Manipulation: Containing plain instructions in the theory and practice of the arts of Photography, Calotype, Cyanotype, Ferrotype, Chrysotype, Anthotype, daguerreotype, Thermography, published by George Knight and Sons, 1843 p.37
Robert Hunt experimented with organic and inorganic light-sensitive substances
Hunt, like most discoverers, also published his work in many instances. One of the most important to the anthotype process is Researches on Light.
Robert Hunt. Researches on Light; an Examination of All the Phenomena Connected with the Chemical and Molecular Changes Produced by the Influence of the Solar Rays, (1844).
Available free on Google Play: https://play.google.com/store/books/details?id=GqoaAAAAYAAJ
Mrs Mary Somerville published her research through a letter to Sir John Herschel dated September 20, 1845
Mrs Mary Somerville shares her experiments in a very elaborate letter to Sir John Herschel, describing Somerville’s important research on the “action of rays” using the spectrum of light to determine the effect it had on vegetable juices. Here is an example of her report:
“On the juice of Plumbago auriculata the lavender and violet rays produced a pale brown image; the indigo rays had no effect, while all the rest of the image under the mean and least refrangible rays was blue and indigo.”
Somerville builds on Herschel’s previous experiments and researches the effects of the different rays in the spectrum. She found red and orange rays had very little, if any, effect on the tinctures; on the other hand, yellow and green were very effective, and indigo somewhere in between. She often adds substances such as borax and Sulphuric acid to her tinctures (but please don’t do this!);long-term exposure can have an effect on your health.
Mrs Mary Somerville, ‘On the Action of the Rays of the Spectrum on Vegetable Juices. Extract of a Letter from Mrs. M Somerville to Sir J.F.W. Herschel, Bart., dated Rome, September 20, 1845. Communicated by Sir J. Herschel. Received November 6, – Read November 27, 1845,’ published in the Philosophical Transactions of the Royal Society of London, 136 (1846), p.111-120.
The original handwritten letter by Mrs Mary Somerville:
Extract, ‘On the action of the rays of the spectrum on vegetable juices’ from a letter from Mrs M [Mary] Somerville to Sir J F W [John Frederick William] Herschel. Reference number PT/30/8. Date 20 September 1845