What is the oldest surviving photograph?

first photographAmong the first experiments carried out to obtain images by means of light are those carried out in 1802 by Thomas Wegwood and Humphry Davy on light-sensitive paper, on which they placed colored crystals, insect wings and leaves. These images could not be fixed and have been completely lost.

in 1816 Joseph Nicephore, a native of Chalon-sur-Saone, France, managed to capture the image of a landscape in true colors, but Nicéphore did not have the means to fix them. Over time the image was lost.

older-photograph

Years later, in 1826, Nicéphore himself managed to take with a camera obscura the same image from his attic window. He used a polished sheet of pewter (an alloy of zinc, lead and tin) on which he applied a layer of Judean bitumen mixed with petroleum. Bitumen hardens and whitens when exposed to light. This mixture is therefore photosensitive, meaning it changes if light is shone on it, but not sensitive enough to take an image quickly.

Nicéphore exposed the landscape for eight hours, the time necessary for the light to whiten the bitumen. The photograph shows a curious arrangement of lights and shadows, as the Sun changes position throughout the day.

The Judean bitumen hardened and whitened in the areas that received more light, resulting in a positive image, instead of a negative one as in current cameras. At the end of the exposure, Nicéphore cleaned the plate with petroleum solvent and then applied iodine vapor to it to increase the contrast with the white parts. This photo is blurry and you can only see the image at oblique angles, but you can recognize the buildings and trees on Nicéphore’s farm.