The earliest processes invented and introduced to produced one of a kind mechanical pictures, the reproduced the subject accurately. The clarity of picture created uneasiness with the viewer as the unaccustomed detail and the unaccustomed truth to nature of the daguerreotype. Some of the audience believed that the tiny figures being reproduced actually were alive and able to see out.

The Daguerreotype was introduced in 1839 the process consisted of exposing copper plates to iodine, with the fumes created forming light-sensitive silver iodide. The plate would have to be used within an hour. The plate would be exposed to light, between 10 and 20 minutes, depending on the available light. The plate was then developed over mercury heated to 75 degrees Centigrade. This causes the mercury to amalgamate with the silver. The image was then “fixed’ to the plate in a warm solution of common salt (followed by sodium sulphite) and the plate finally being rinsed in hot distilled water.

The Ambrotype was developed in the mid 1850’s. A glass negative was made positive by coating its back with black lacquer. Lacking the tonal range of the daguerreotype, the main advantage was that they were less expensive, but the glass was fragile and often broke, destroying the image.

The Tintype developed during the Civil War in the 1860’s. Here a piece of iron was coated with the light sensitive materials. Much easier, and safer to transport, while being far less expensive than glass. All of these processes were to succumb to two major photographic developments: the paper image and the reproducible negative.

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