Today in 1839 Louis-Jaques-Mandé Daguerre, a French artist and photographer, introduced the Daguerreotype, the first practicable method of obtaining permanent images with a camera.
The Daguerreotype photographic process starts with a sheet of silver-plated copper polished to a mirror finish, treated with fumes of iodine and bromine to make its surface light sensitive. exposed in a camera (for as long as fifteen minutes) and then developed over hot mercury, fixed by immersion in a solution of sodium thiosulfate and washed with distilled water.
The George Eastman Museum explores the history and development of the Daguerreotype in the video below.