Introduction to photography

The coining of the word "photography" is usually attributed to Sir John Herschel in 1839. It is based on the Greek φῶς (phots), (genitive: photo's) meaning "light", and γραφή (graphê), meaning "drawing, writing", together meaning "drawing with light".

method of recording the image of an object through the action of light, or related radiation, on a light-sensitive material.

Antecedents

• a dark chamber or room with a hole (later a lens) in one wall, through which images of objects outside the room were projected on the opposite wall.​

• The principle was probably known to the Chinese and to ancient Greeks such as Aristotle more than 2,000 years ago

• Late in the 16th century, the Italian scientist and writer Giambattista della Porta demonstrated and described in detail the use of a camera obscura with a lens. While artists in subsequent centuries commonly used variations on the camera obscura to create images they could trace, the results from these devices depended on the artist’s drawing skills, and so scientists continued to search for a method to reproduce images completely mechanically.

Daguerreotype

​Niépce's experiment led to a collaboration with Louis Daguerre. The result was the creation of the daguerreotype, a forerunner of modern film.

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• A copper plate was coated with silver and exposed to iodine vapor before it was exposed to light.

• To create the image on the plate, the early daguerreotypes had to be exposed to light for up to 15 minutes.

• The daguerreotype was very popular until it was replaced in the late 1850s by emulsion plates.

• ​Emulsion plates, or wet plates, were less expensive than daguerreotypes and required only two or three seconds of exposure time. This made them much more suited to portrait photographs, which was the most common use of photography at the time. Many photographs from the Civil War were produced on wet plates.