Photography as a practical process began when Jacques Daguerre discovered a way to fix, or make permanent, the images cast on silver-coated copper plates treated with light-sensitive iodide. The metallic plates were exposed as the light traveled through a camera lens, changing the chemical composition of the plates. These were then treated with a mercury vapor, a process that converted the emergent image from a negative to a detailed, positive picture.

The last step in the process made the images permanent. Once the exposed plates had been rinsed in a hot saltwater solution that dissolved the silver iodide that had not been affected by light, the images were fixed and did not fade when exposed to light. Variations of the developing process continued to be an integral part of film-based photography.

As advantageous as this process appeared, there were important limitations. The lengthy exposure time required for success was the greatest drawback to the earliest daguerreotypes, initially making attractive portraits impossible. Each picture required a repetition of the entire process on new plates, and the equipment was frequently judged too cumbersome for practical fieldwork. Also, the fragile images damaged easily and could be seen only when viewed from an angle, due to the glare produced by the silver coating on the plates.

Freed from patent restraints by the public announcement of Daguerre's process, entrepreneurial camera designers rapidly improved the lenses and other mechanical features of cameras. For example, a mirror prism placed in front of the lens corrected the reversed images produced by the original cameras. Another inventor created a camera that relied on concave mirrors to reflect images rather than passing light through a lens.

New lens combinations, widened apertures, and an improved chemical process further reduced long exposure times. Antoine Claudet discovered that treating the silver-coated copper plates with both iodide and chlorine greatly accelerated their sensitivity to light. Thus, it became possible to take portraits in the shade in only five to twelve seconds and in full sunshine in only one to four seconds.

Photo-etching methods of deriving prints from finished plates enabled printers to duplicate copies of the originals for publications, but this process was difficult and never became practicable. However, daguerreotypes were used to increase accuracy and to reduce the production time involved in creating lithographs and traditional engravings. By 1847, French photographers had begun to favor a paper-based process developed by William Fox Talbot.

An important new process introduced in 1851 by Frederick Scott Archer that utilized glass plates dipped in a solution containing collodion, or nitrocellulose, contributed to a marked decline in daguerreotype production. Nevertheless the striking, silvery images continued to be highly prized in the United States for many years. Recent interest in the daguerreotype has led to a renewed use of the process, primarily for aesthetic reasons.

Free term papers are not written to satisfy your specific instructions. You can use our professional writing services to buy a custom written research paper, term paper, or essay on Technology at affordable price. CustomTermPapers is the best solution for those who seek help in writing term papers, essays, and research papers related to Technology and other relevant topics.