The Camera Obscura is an ancient optical device. In its most basic form it is, quite simply, a dark room with a small hole in one wall. On the wall opposite the hole, an image is formed of whatever is outside. This image is upside-down (inverted) and back to front (laterally transposed).
2. Daguerreotype:
The daguerreotype was the first commercially successful photographic process (1839-1860) in the history of photography. Named after the inventor, Louis Jacques Mandé Daguerre, each daguerreotype is a unique image on a silvered copper plate.
3. Calotype (Talbotype):
Calotype, also called talbotype, early photographic technique invented by William Henry Fox Talbot of Great Britain in the 1830s. In this technique, a sheet of paper coated with silver chloride was exposed to light in a camera obscura; those areas hit by light became dark in tone, yielding a negative image. The revolutionary aspect of the process lay in Talbot’s discovery of a chemical (gallic acid) that could be used to “develop” the image on the paper, accelerate the silver chloride’s chemical reaction to the light it had been exposed to. The developing process permitted much shorter exposure times in the camera, down from one hour to one minute.
4. Collodion Wetplate:
Collodion process, mostly synonymous with the "collodion wet plate process", requires the photographic material to be coated, sensitized, exposed and developed within the span of about fifteen minutes, necessitating a portable darkroom for use in the field. Collodion is normally used in its wet form, but can also be used in humid ("preserved") or dry form, at the cost of greatly increased exposure time. The latter made the dry form unsuitable for the usual portraiture work of most professional photographers of the 19th century. The use of the dry form was therefore mostly confined to landscape photography and other special applications where minutes-long exposure times were tolerable.
5. Dorothea Lange:
Dorothea Lange was a photographer whose portraits of displaced farmers during the Great Depression greatly influenced later documentary photography.
6. Lewis Hine:
Lewis Hine was trained to be an educator in Chicago and New York. A project photographing on Ellis Island with students from the Ethical Culture School in New York galvanized his recognition of the value of documentary photography in education. Soon after, he became a sociological photographer, establishing a studio in upstate New York in 1912. His photographs were instrumental in changing child labor laws in the United States.
7. Mathew Brady:
Mathew B. Bradywas one of the earliest photographers in American history, best known for his scenes of the Civil War. He studied under inventor Samuel F. B. Morse, who pioneered the daguerreotype technique in America. When the Civil War started, his use of a mobile studio and darkroom enabled vivid battlefield photographs that brought home the reality of war to the public. Thousands of war scenes were captured, as well as portraits of generals and politicians on both sides of the conflict, though most of these were taken by his assistants, rather than by Brady himself.
8. Eadweard Muybridge
Eadweard Muybridge (Edward James Muggeridge) was an English photographer important for his pioneering work in photographic studies of motion, and early work in motion-picture projection. He adopted the first name Eadweard as the original Anglo-Saxon form of Edward, and the surname Muybridge believing it to be similarly archaic.