Barricades in the streets of Paris during the French Revolution; August 25th, 1848
The most common way to take a photograph in 1848 was the Daguerreotype, invented by Louis-Jaques-Mandé Daguerre in 1830. He and his partners didn’t start to commercialize it until 1839, and so when Thibault took this image, he was using a technology only nine years old.
It wasn’t easy to take a Daguerreotype. You need a sheet of silver-plated copper, polished to a mirror finish. The slightest imperfection means the image is marred, so you have to keep it as pristine as possible. You take that sheet, then treat it with chemical fumes. Working quickly, in the dark ─ the fumes make the sheet light-sensitive ─ you shove the sheet into your camera, which is little more than a wooden box with a simple hole in the front. That hole is covered with a simple glass lens, itself concealed by a leather or fabric lens cap.
When you judge the time is right, you remove the lens cap and wait. How long you have to wait depends on how bright the scene is. If you’re in bright sunlight, you only need a few seconds. If you’re working indoors or on a dark day, it might take minutes. You have to keep the camera perfectly still on its tripod ─ any vibrations will blur the image. An 1841 instruction manual indicates, “For an exposure by overcast, dark skies in winter 3 ½ minutes is sufficient; on a sunny day in the shade 1½ to 2 minutes are enough, and in direct sunlight it requires no more than 40-45 seconds. The last, however, is seldom employed on account of the deep shadows necessarily obtained.”
When you think you’ve got it (estimating the precise time necessary was by guess, until experience allowed the creation of timing charts), you put the lens cap back on.
To develop the image you have to ─ again, working in the dark ─ expose the chemically treated sheet to mercury vapor, a substance we now know is incredibly toxic. Once done, the sheet has to be washed by a chemical that removes its light sensitivity. Rinse the sheet, then dry it, taking particular care to avoid rubbing against the sheet. The image is so easily marred that you can scuff it or erase parts of the image even with the lightest wiping.
Once the sheet’s done, you immediately put it into a glass case to avoid touching it ever again.
Imagine Thibault doing all of this from a top-floor apartment at 7:30 a.m. on June 25, 1848. That’s exactly when this image was taken. As Thibault crouched over his camera, the soldiers of General Louis Eugène Cavaignac were marching on Paris. Cavaignac had been serving with the French Army in Algeria, where he had a reputation for brutality against the native population. Facing him in Paris were an estimated 170,000 working-class Parisians furious at the government’s closure of a series of make-work factories designed to alleviate unemployment.
Thibault knew what was coming, and so did the other people on his street. You can see it in the closed shutters up and down the road. Since February, the liberal and radical workers of Paris had been protesting, rioting and simply arguing against the government.
But Thibault stayed over his camera, an early-Victorian nerd eager to preserve the moment rather than preserve his own safety. In the end, he not only took this picture, he went back 24 hours later to take another, and the resulting stereo effect shows what happened before and after Cavaignac and his soldiers moved in.