Ferdinand Hurter (1844-1898) and Vero Charles Driffield (1848-1815)
The Mathmaticization of Photography
There was a profound shift (a paradigm shift in the Kuhnian sense) in the perception of photography around 1880. From 1839 until the mid 1870s, discussions of photography were largely qualitative, e.g. is it an art or a science?
General public sentiment, as far as I can tell, was not overwhelmingly positive in this regard—photography was seen as a lesser method of depicting actuality. However, given its cheapness, it was more accessible to the public at large who could not afford the services of most painters or artists. The science of photography was largely of an alchemical sort. The scientific questions were also qualitative, due to the failure of photographic “evidence” to fit existing theories of the behavior of light. Were there new “imponderables” (phenomena without mass) to contend with besides light, heat, magnetism, and electricity? The questions were ones of kind, not relationship. That is, until Hurter and Driffield.
James Clerk Maxwell suggested in 1862 that magnetism, electricity, and light were all manifestations of a larger electromagnetic spectrum. However, it wasn’t until he published Electricity and Magnetism in 1873 that the idea began to take hold. Suddenly, the questions asked about the behavior of photosensitive materials took a different form. They became mathematical in nature: what was the relationship between exposure to light and photographic material? Instead of questioning the qualitative nature of light, as researchers such as Hunt and Draper had done, researchers began to look for better methods of measuring light quantitatively and exploring the relationship between exposure and response in photographic materials.
The birth of photography as a modern science seems to have occurred circa 1880, with the invention of the actinograph (light meter) by Hurter and Driffield and the first motion studies of Muybridge. Both these efforts were carefully measured and mathematical in nature. The intense period of experimentation in the 1880s was fueled both by a technological need and a desire to have proof of a measurable nature. The shift during this time from relatively forgiving wet plates and the more tricky but convenient dry plates was part of the equation—photographers needed better instrumentation than “rules of thumb” to get consistent exposures. However, the one of the first uses of the actinograph was to mathematically establish the relationship between the position of the sun in the sky to light intensity. Motion studies were used to establish the relationships between muscle groups and motion, rather than to create more accurate depictions of motion. At issue in both types of research were matters of detection rather than depiction.
The culmination of Hurter and Driffield’s research was the characteristic curve used to measure photosensitive materials—named the H&D curve in their honor. With the discovery that there was a mathematical relationship between exposure, development, and density in photosensitive materials in 1890, photography became scientific in the modern sense. Reading the papers of Hurter and Driffield, I am struck by their desire to improve the consistent reproducibility of photographic copies—at a time when the halftone was making mechanical reproduction of photographic facsimiles in print truly possible.
It was another decade before photography in print really proliferated, but I can’t help but think that this groundwork in mathematics had a lot to do with it.