The invention of cinema.
Operation of the CINEMA PROJECTOR
The first was the creation of cinematographic cameras (derived from cameras to photograph) and later, the creation of film projectors.
The operation of both is the following:
Gear wheels inside the cameras and projectors adhere to perforations to move the film at a constant rate.
Subsequently, the light of the projector is closed, while the film moves to place the next frame, when it is placed the light is passed and the new image is projected, and so on.
Through a lamp and a lens, to focus, the images or frames are projected.

The number of frames per second is the speed or rate at which a device displays images called frames.
When you exceed 10 frames per second, the brain will perceive them as movement and not individually.
Number of frames per second:
In the Silent Cinema is 16.
In the Analogue Cinema it is 24.
And in digital cinema is 30 or more.
The more images per second, the more definition will be observed.

 

The second part in the creation of the cinema is THE RETINIAN PERSISTENCE.
Demonstration of reality, and what the human eye observes, at a very slow speed.
When you stop projecting the image you will continue to see, because the brain retains the impression of light.

This is the retinal persistence, an optical phenomenon by which the retina preserves for some time the printing of the images, (for approximately 0.1 seconds).
When the speed of projection is very slow, people notice small interruptions of darkness.
Speed of 8 frames per second.
But when it exceeds 10 frames per second, the brain will perceive them as movement and not individually.

Speed of 12 frames per second.

the images are superimposed on the retina, and the brain "links" them as a single, moving and continuous visual image.

For this reason the cinematographic films are perceived with natural continuity, without noticing the transitions of the frames.