The DoMeBo Photography ClassLesson #2 – “A Photographic History”
The delay in getting to this lesson was much longer than I expected, and I apologize for my absence in the many weeks since the previous lesson was pretty much finished. This will be a short session as far as the initial lecture goes. If you want a full and complete history of photography, it shouldn’t be too hard to find good timelines on Wikipedia and elsewhere.
Photography came as a culmination of a variety of technologies and techniques in the first half of the 19th Century. Specifically:
Camera Obscura
A camera obscura (or pin-hole camera) causes light coming through a tiny hole to project an upside-down image inside a dark chamber, be it a small box or an entire room. This is the same thing as in a modern camera, only without a lens and without film.
Lenses
Mathematical and practical work on the magnification and focusing properties of lenses got better and better over time. Some were attached to camera obsucra holes. This combination is essentially what your camera is.
Chemicals
Certain chemicals were discovered to change color and/or darken when exposed to light, silver compounds such as Silver Nitrate and Silver Chloride are prominent examples. The next step to a photograph is to get such materials to stay around.
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Photography
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Frenchman Nicéphore Niépce used “Bitumen of Judea,” made from petroleum, which became hard and insoluble upon exposure to light, smeared on a smooth metal plate. When exposed, areas of an image that were darker could be washed away while the light areas would remain. (The picture on the right was taken without a lens, and the exposure time was eight hours.)
Niépce switched to silver compounds, which darkened with light, and along with Louis Daguerre kept working on it. After Niépce’s death, Daguerre finalized the process using silver on top of copper plates. Thus the widely-used 19th century “daguerreotype” process. Nice ego there, Louis.
Film
Flash forward to the 1880s, when George Eastman invented photographic film on a roll. This allowed extreme portability compared to the metal plates used in daguerreotypes and other early photographic processes. First used with the original "Kodak Camera," this technology went mainstream with the inexpensive Brownie camera in 1900. The 35mm Leica camera came out in 1925 and not too much has changed.
Well, except for...
Digital
The CCD was invented at the venerable Bell Labs in 1969 by Willard Boyle and George E. Smith. A CCD takes on a charge from the exposure of light and is able to record it as digital information via a processor. Although very low resolution at first, they eventually got to the point that, with large enough megapixel counts, large prints could be made from the images.