James Polchin at The Smart Set:
The camera her daughter and son-in-law gave her that winter was a heavy machine, awkward to move around, made of wood and the size of a large birdhouse. It was the most modern of its time. We can easily forget today how arduous and dangerous the process of photographing was back then. The glass plates used to expose the image (the forerunner to film) were there own chemistry lab, requiring a coating of a thick and flammable collodion solution, followed by a quick dash to the camera to insert the class behind the lens and expose it to the light before the plate dried. Then, through a series of sliver nitrate washes (the fumes could be deadly) and drying, washing and drying again, the glass negative was ready to transfer its image to the prepared albumen paper that was brushed with a frothy mixture of egg white and silver nitrate to give the paper a glossy texture. The plate was placed on the paper, exposed to the sun, and then, it too was washed and let dry. At any one point in this process, the photographs could easily be destroyed. This mixture of science and art burdened these practices with certain standards of skill. Photography was still considered a scientific experiment; it’s practitioners more akin to chemist than artists. What constituted a good photograph was as much about the process as the composition.
While there is little evidence that she was much interested in visual art before the 1860s, Cameron took to this process with her usual energy. Her interest was in what this process can create more than what it should create.
more here.