Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either chemically via a light-sensitive material such as photographic film, or electronically by an image sensor. 


An old style medium format came, displayed at the Deutsches Museum, Munich. image: R.Conan-Davies

Typically, a lens or mirror combination (optical visual technology) is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure. The light is essentially sensed by an electronic surface or chemically reactions with a surface. 

Electronic photographs

 In an electronic image sensor ( often a CCD or CMOS)  light (photons) produce an electrical charge at each pixel which is processed and stored in a digital image file for subsequent display or further processing within the camera or other software. 


A CCD Sony ICX493AQA 10.14 APS-C . image: Andrzej w k 2 /wikipedia

Chemically based

The result in a photographic emulsion is an invisible latent image, which is later chemically developed into a visible image, either negative or positive depending on the purpose of the photographic material and the method of processing. 

Layers of 35mm color film: 1. Film base; 2. Subbing layer; 3. Red light sensitive layer; 4. Green light sensitive layer; 5. Yellow filter; 6. Blue light sensitive layer; 7. UV Filter; 8. Protective layer; 9. (Visible light exposing film). image: wikipedia /I, Voytek S

A negative image on film is traditionally used to photographically create a positive image on a paper base, known as a print, either by using an enlarger or by contact printing.

Photography has many uses for business, science, manufacturing (e.g. photolithography), art, recreational purposes, and mass communication.

A brief history of the first photography process

The first chemical photographic process was the Daguerreotype process, or daguerreotypy. This was the first publicly available photographic process, and for nearly twenty years it was the one most commonly used.

Invented by Louis-Jacques-Mandé Daguerre and introduced worldwide in 1839, daguerreotypy was almost completely superseded by 1860 with new, less expensive processes yielding more readily viewable images. During the past few decades, there has been a small revival of daguerreotypy among photographers interested in making artistic use of early photographic processes.

Daguerre did not patent and profit from his invention in the usual way. Instead, it was arranged that the French government would acquire the rights in exchange for a lifetime pensions to Daguerre and to Niépce's son and heir, Isidore. The government would then present the daguerreotype process "free to the world" as a gift, which it did on 19 August 1839. This date has become #WorldPhotographyDay . source