Daguerreotype 1840

Daguerreotype was the first commercially used type of printing process for photography. The positive image is copied directly onto a silver covered copper plate. The surface of a Daguerreotype is like a mirror and must be angled in certain ways in order to properly view the image that has been burned into it. At some angles the image can change from positive to negative. Daguerreotypes are very fragile and sensitive and can easily be rubbed off the silver surface. The process in which the silver coated copper plate is prepared makes the silver sensitive to light. When a scene is projected onto the silver it results in a latent image (essentially an invisible image). The latent image was made visible by placing it over a slightly heated cup of mercury. The mercury vapor condensed the silver where there was a lot of light exposure and less on the areas that were exposed to less light, revealing an image. Then, the image needed to be permanently "fixed" onto the plate. This was done by using a chemical, hyposulphite of soda, which today is called fixer. Because of Daguerreotype's sensitivity, most prints were protected by a glass plate cover. This process was slow and difficult, but was the first commercially used way to document scenes using camera obscuras.