American Daguerreotypes, 2002 Digital collage 20 x 24 inches

A Brief History of Daguerreotypy

The New Art,---We saw the other day, in Chilton's, in Broadway, a very curious specimen of the new mode, recently invented by Daguerre in Paris, of taking on copper the exact resemblances of scenes and living objects, through the medium of sun's rays reflected in a camera obscura. The scene embraces a part of St. Paul's church, and the surrounding shrubbery and houses, with a corner of the Astor House, and for aught we know, Stetson looking out of a window, telling a joke about Davie Crockett. All this is represented on a small piece of copper equal in size to a miniature painting.
--New York Morning Herald, September 30, 1839

The Process

A daguerreotype is made on a sheet of silver-plated copper. The surface is polished to a mirror like brilliance and made light-sensitive by coating with iodine fumes. The plate is then exposed to an image sharply focused by the camera's well-ground, optically correct lens. Removed by the camera, the plate is treated with mercury vapors in order to develop the latent image. Finally, the image is "fixed" by removing the remaining photosensitive salts in a bath of "hypo" (sodium thiosulfate) and toned with gold chloride to improve contrast and durability. Color, made of powdered pigment, was applied directly to the metal surface with a finely-pointed brush.
The first camera's required a lengthy exposure time lasting many minutes. By the 1840s various optical means had reduced the exposure time to three or at most five minutes, and by the end of the decade to a matter of seconds. Daguerreotypists learned that their plates were more sensitive in dry weather than in damp, and that just before a thunderstorm their exposures were the shortest. Until cameras were equipped with a mirror to correct the error, daguerrean images remained reversed from right to left.

The photograph above is Samuel Morse's Daguerreotype Camera

Standard Daguerreotype Sizes
Whole plate - 6 1/2 by 8 1/2 inches
Half plate - 4 1/4 by 5 1/2 inches
Quarter plate - 3 1/4 by 4 1/4 inches
Sixth plate - 2 3/4 by 3 1/4 inches
Ninth plate - 2 by 2 1/2 inches
Sixteenth plate - 1 3/8 by 1 5/8 inches