Louis Daguerre was a professional scene painter for the opera, who was interested in the effects of lighting. He began experimenting with the effects of light upon the translucent paintings in the 1820s. During this time he used a camera obscura to aid painting with perspective, which sparked his interest in finding a way to keep the image still. In 1829, Daguerre began a partnership with Joseph Niepce in order to improve upon the photography process which Niepce had invented, where the photographs quickly faded. After several years of experimentation, Daguerre developed a more convenient and effective method, which is now known as the daguerreotype. Some believed his discovery was a mistake; In 1835, he put an exposed plate in his chemical cupboard, and a few days later he found that the latent image had developed. Daguerre concluded the development of the photograph was caused by the presence of mercury vapor from the broken thermometer, which later led to the discovery that future images could be developed with a shorter exposure time.
PROCESS:
The daguerreotype was the first commercially successful photographic process, where a highly detailed image is a direct positive made in the camera on a silver plated copper plate. This sliver-plated copper plate had first to be cleaned and polished until the surface looked like a mirror. Next, the plate was sensitized in a closed box over iodine until it took on a yellow-rose color. The plate, which was held in a lightproof holder, was transferred to the camera. Once the sensitized plate was placed in the camera, the lens cap would be removed in order to being the exposure. After exposure to light, the plate was developed over hot mercury until the image appeared. To fix the image, the plate was immersed in sodium thiosulfate or salt and toned with gold chloride.
The exposure times for the first daguerreotypes ranged from 3 to 15 minutes, making the process impractical for portraits. Later modification to the sensitization process and improved photographic lenses helped reduce the exposure time to less than a minute. Daguerreotypes could also copied thought a process known as "redaguerreotyping".
- Whole plate 6-1/2" x 8-1/2"
- Half plate 4-1/4" x 5-1/2"
- Quarter plate 3-1/4" x 4-1/4"
- Sixth plate 2-3/4" x 3-1/4"
- Ninth plate 2" x 2-1/2"
- Sixteenth plate 1-3/8" x 1-5/8"
CAMERAS:
The earliest cameras were made by opticians and instrument makers, and sometimes by the photographers themselves. Most cameras utilized a sliding-box design, with the lens placed in the front box. The second, slightly smaller box slid into the back of the larger box. Focus was controlled by sliding the rear box forwards or backwards. A laterally reverse image would be obtained (unless the camera had a mirror or prism to reverse the image on the plates).
-HCM-
Week 3
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