PHOTOGRAPHING.

Centuries ago, many scientists have observed that many chemical materials color could be changed under the affection of light, by other meaning it's light sensitive.
Light, for example, makes a dark effect on the silver derivatives after processed with specific chemical materials. especially the silver bromide, which is used in processing the photographic films or optical films.

Talbot Fox

There is a punch of films all of it contains at least one layer sensitive to light which is Emulsifier. and in the white/black movie, the Emulsifier is a combination of a gelatine layer that includes a micro silver bromide objects painted over an elastic base or glass.
The camera works on focusing the incoming or the reflected light from the spotted body when opening the seal towards the emulsifier, the incoming light from different parts of the spotted body affects the silver bromide with various rates according to light intensity, this is how the image form on the film that doesn't completely show up until the film is resolute.

Joseph Niepce

The film resolution processes with special chemical materials in a light prevented environment, so the film doesn't get affected by the incoming outer light, the film then is soaked in the resolution element with 20 degrees Celcius, and the resolution element shows dark spots correlates to the variations of  light's affection on the spotted body. 

after washing the film with water, it's immersed in a chemical solution like the "Hibo" in order to melt down the silver bromide which did not affect with light and to fix the formed image in the film then the film washed and dried.

In order to have a photo from this negativity, the negativity lay on a special photographic paper which contains a layer of light-sensitive micro-crystals, then the photographic paper and the film exposed to a light flash, then the light flash passes strongly through the negative parts of the film very slightly but passes through the clean parts strongly. the photographic paper is then processed to get the final image like the film is processed.

Louis Daguerre

The "Polaroid" camera uses in the modern days uses a special type of films. it's been resolved inside the camera. you can have a colored photo in 10 seconds. also, you can have an x-ray photo with the same way.

"Joseph Niepce" (1765 - 1833) presented the first photographic image by exposing a light-sensitive surface to flash beam in a Camera in 1826. and he worked for a long time with "Louis Daguerre" (1787 - 1851). Together they developed film-making process, Louis Daguerre continued working alone after Joseph's death, "Talbot Fox" followed another way of resolving photographic film that is very similar to the current resolving ways we use today to gain small negatives in 1835.