The calotype process was created by William Henry Fox Talbot (1800-1877) in the very early days of photography. Athough Talbot was not the originator of photography, his calotype formed the basis of the photographic process for more than 150 years.
The calotype, or Talbotype, process will be recognizable to anyone who is familiar with developing photographs. Calotype is derived from the Greek, meaning literally "good impression." Talbot used high-quality writing paper coated with light- sensitive silver chloride. The paper had to be prepared before exposure to light, and then needed ten to fifteen minutes of exposure time in bright light, usually sunlight. The paper was exposed to the light in a wooden box functionally similar to a modern camera.
Talbot also realized that short exposure of the light-sensitive paper and then chemical fixing could produce a useful negative. The fixing process removed the light-sensitive silver, making the negative easier to handle. The negative also allowed multiple "positive" images to be printed, so Talbot's invention was the direct ancestor of the developing, fixing, and printing processes still used today.
`Simultaneous to Talbot's work, Louis Daguerre was developing the daguerreotype process. This process was more akin to a Polaroid than a traditional photograph. The daguerreotype was available ahead of the calotype and was initially very popular, but the lack of a reusable negative meant that the calotype process soon came to dominate photography.
