History
of Photography

The
metal-based daguerreotype process soon had some competition from the
paper-based calotype negative and salt print processes which was invented by
Henry Fox Talbot. Subsequent innovations decreased the required camera exposure
time from minutes to seconds then to a small fraction of a second; this
introduced a new photographic media which were more economical, sensitive or
convenient. This also included roll films for casual use by amateurs and made
it possible to take pictures in natural colour as well as black and white. The
commercial introduction of computer-based electronic digital cameras in the
1990s soon revolutionized photography. During the first decade of the 21st
century, traditional film-based photochemical methods were increasingly
marginalized as the practical advantages of the new technology became widely
admired and the image quality of moderately priced digital cameras was
continually improved.

The
oldest living photograph of the image formed in a camera was created by Niépce
in 1826 or 1827. It was created on a polished sheet of pewter and the
light-sensitive substance was a thin coating of bitumen, a naturally occurring
petroleum tar, which was dissolved in lavender oil, added to the exterior of
the pewter and allowed to dry before use. After a very long exposure in the
camera, the bitumen was hardened in proportion to its exposure to light that
the unhardened could be taken off with a solvent, leaving a positive image with
the light regions represented by hardened bitumen and the dark regions by bare
pewter. To look at the image plainly, the plate had to be lit and seen in such
a way that the bare metal appeared dark and the bitumen relatively light.
Niépce suddenly died in 1833, leaving
his notes to Daguerre. This man was more interested in silver-based processes
than Niépce and had experimented with photographing camera images directly onto
a mirror-like, silver-surfaced plate that had been fumed with iodine vapor
which reacts with silver to form a coating of silver iodide. The result
appeared as positive when it was suitably lit and viewed, with the bitumen
process. But exposure times were still incredibly long until Daguerre made a
discovery that and invisibly “latent” image produced on such a plate by a
shorter exposure could be developed to full visibility by mercury fumes. This
discovery brought the required exposure time down to a few minutes under
optimum conditions. January 17, 1839, this first complete practical
photographic process was announced at a meeting of the French Academy of
Sciences and the news spread quickly.
William Henry Fox Talbot, a man who
succeeded in creating stabilized photographic negatives on paper in 1835,
worked on perfecting his own process after he had finished reading early
reports of Daguerre’s invention. William acquired a key improvement from John
Herschel who had shown that hyposulfite of soda would dissolve silver salts.
This news reached Daguerre and he had substituted it with his less effective
hot water treatment.
William’s silver chloride “sensitive
paper” experiments had required camera exposures of an hour or more. A year
later, William invented the calotype process which was kind of like Daguerre’s
process which used the principle of chemical development of a faint “latent”
image to reduce exposure time to a few minutes. Silver iodide coated paper was
exposed in the camera and developed into a translucent negative image. Unlike
the daguerreotype, a calotype negative could be used to make a large number of
positive prints by simple contact printing.
In 1839, John Herschel made the first
glass negative. In 1841, Slovene Janez Puhar invented a process for making
photographs on glass. In 1847, Niépce St. Victor published his invention of a
process for making glass plates with an albumen emulsion. In the mid-1840s, the Langenheim brothers of
Philadelphia and John Whipple and William Breed Jones of Boston also invented
workable negative-on-glass processes. In 1851, Frederick Scott Archer invented
the collodion process.

In 1957, a team led by Russell A.
Kirsch at the National Institute of Standards and Technology developed a binary
digital version of an existing technology, so that alphanumeric characters,
diagrams, photographs and other graphics could be transferred into digital
computer memory. Dr. Michael Tompsett discovered that the CCD could be used as
an imaging sensor. The CCD has been replaced by the active pixel sensor,
commonly used in cell phone cameras.
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