Louis Daguerre (1787-1851), with an illustration of the camera he invented. Image Credits: Everett Historical/shutterstock.com
In order to better understand the scientific importance of photography it is necessary to explore the medium from its inception in the nineteenth century.
Photographs are now such a commonly used visual form of capturing and categorising our experiences and surroundings that it is difficult to imagine a world in which photography did not operate.
It is impossible to avoid the saturation of photographic images we endure on a daily basis in the news and on social media. Photography’s accessibility as a social tool may cloud our understanding of its pragmatic and practical uses in scientific innovation and examination.
"I have seized the light! – I have arrested its flight!"
In 1839, the French illusionist and artist Louis Daguerre proclaimed, “I have seized the light! – I have arrested its flight!” Daguerre had been collaborating with the scientist Joseph Niépce, who had invented the heliograph photographic process in the 1820s, producing what remains the earliest surviving photograph made using a camera.
The Heliograph Process
The heliograph process worked by taking an image on which the black portions did not allow any light to pass through and placing it on top of a prepared pewter plate coated with bitumen. The bitumen becomes white and insoluble when exposed to sunlight. Oil would be used to dissolve the remaining dark areas of the image.
Heliography developed over time and by the mid-nineteenth century it was utilised as an affordable method for the reproduction of technical drawings and diagrams. The eventual use of ferro-prussiate paper resulted in a white design on a blue background, giving rise to the term 'blueprint'.
The Daguerreotype Process
What gave Daguerre the incentive to make the claim that it was he who had seized the light? Other than being an egotistical showman, Daguerre improved the process by using silver-plated copper sheets with iodine, thus making the plate light-sensitive, that were exposed in a camera before the image was developed with warm mercury vapour. This revolutionised the photographic process in terms of efficiency.
A daguerreotype, created within half an hour, was superior in contrast to the eight hour exposure time involved in Niépce’s first heliographic image. By 1842, capturing an image could take as little as a minute.
Daguerreotype of Portsmouth Square with restaurants and shops, San Francisco, 1851. Image Credits: Everett Historical/shutterstock.com
"From today, painting is dead"
In a 'Daguerreotypomania' that gripped the western world, photography emerged as a powerful force in both science and art. The mechanical process obliterated the elitist inaccessibility of painted portraiture, supposedly shocking the artist Paul Delaroche into proclaiming, "from today, painting is dead".
Daguerre carefully promoted his invention on both fronts. Photography’s use as an objective technique of accurate observation placed it in high regard amongst scientists of the era. Prior to photography, scientists had to rely on subjective sketches of natural observations, often missing crucial details.
The Scientific Uses of a Daguerreotype
One of Daguerre’s earliest photographs included an arrangement of shells and fossils. Before the Académie des Sciences exhibited the daguerreotype process, one journalist wrote of seeing an image of a dead spider taken through a solar microscope, "You could study its anatomy with or without a magnifying glass".
Daguerre first photographed the moon in January, 1839. Unfortunately, in March of that year his laboratory burnt to the ground and the flames consumed much of his early experimental work.
A year later the American doctor and chemist John William Draper took a daguerreotype of the moon, testifying to the speed at which this revolutionary process became a universal force for scientific examination across the western world in the mid-nineteenth century.
By 1850, Draper had collaborated with the astronomer William Cranch Bond to photograph the star Vega, 25 light years from earth.
Back across the Atlantic, the physicists Jean Bernard Léon Foucault and Armand Fizeau had been improving the process in the 1840s by combining the daguerreotype process with an electric light source to illuminate photographic subjects.
The pair’s innovation in the field gained them the attention of François Arago, an observer at the Observatoire de Paris, who asked them to attempt to photograph the Sun.
In this venture they were again successful, capturing the first images of the Sun in which sunspots on the photosphere were visible in 1845.
The Limitations of Daguerreotypes
The daguerreotype process had its limitations. The metal sheets utilised were heavy and cumbersome. They also required a cover plate or frame to protect the delicate surface substances.
Daguerreotype images were unreproducible and the supplies required (a new metal plate for every image) made the process costly, whilst the bulky equipment made capturing a photograph difficult in outdoor environments.
Unbeknownst to Daguerre whilst he conducted his experiments, a British inventor by the name of Henry Fox Talbot was pioneering a different photographic process that mitigated some of the daguerreotype’s faults.
The Work of Henry Fox Talbot
In 1833, the idea occurred to Talbot that it would be "charming to cause… natural images to imprint themselves durably, and remain fixed upon… paper" and a year later his experiments began at Lacock Abbey in Wiltshire.
Embedding a light-sensitive silver chloride into ordinary writing paper, Talbot discovered that when placed in the sun under an opaque object such as a leaf, the paper would darken where not protected from light.
The resulting negative was a sciagraph, a shadow drawing.
For the rest of the decade Talbot laboured to increase the sensitivity of his coatings so that they would be sufficiently suitable for use in a camera.
Although Daguerre was the victor as the first to announce and patent his process, Talbot’s work is deserving of respect and admiration.
The negatives created in his camera required enormous amounts of solar energy.
Further research revealed that using a chemical developer on photographic paper that had only received a short exposure could build latent, often invisible images into full-strength negatives.
Not only did this reduce exposure times from minutes and hours to seconds, the additional step of creating a negative (compared to Daguerre’s direct process) allowed the production of multiple prints. The calotype was the name given to this form of photograph.
An Objective Lens to Science
The processes of both Daguerre and Talbot evidently had their advantages and both were revolutionary processes in terms of scientific observation, categorisation and conservation. They offered an objective lens to science, one believed to be uninhibited by human fault.
However, the invention of the wet-collodion process would surpass both methods. Frederick Scott Archer, a British man of humble origins, would transform and advance the accessibility and affordability of photography whilst retaining the fine detail of the daguerreotype.
Sources and Further Reading