Unlike the printed photographs we’re all accustom to, in which images are printed from transparent negatives onto paper; the daguerreotype (da·guerre·o·type) was a polished copper plate upon which an image was directly exposed. No negatives were used in the process so each daguerreotype was unique.
The process, perfected by Louis-Jacques-Mande’ Daguerro, involved polishing a sheet of silver-plated copper to a mirror finish, treating it with fumes that made its surface light sensitive, exposing it in a camera, then fuming it with mercury vapor, making the image visible. After this they would remove its sensitivity to light using a liquid chemical treatment, rinse it, and then seal it behind glass in a protective enclosure. The darkest area of the images were bare silver; lighter areas had a fine light-scattering texture. The surfaces were very delicate, and even the lightest wiping could destroy it.
This was the first publically available form of photography. Over the next couple of decades it became quite popular with celebrities, politicians, and the American middle class. Daguerreotypes were primarily used for portraits of loved ones, as most were small enough to carry around in your pocket.
Daguerreotypes were eventually replaced by tintypes and CDV’s, but it was daguerreotypes that first introduced the masses to photography, and the first to capture a person in an image (as seen above).