Is the film made by using the principle of visual retention?

The most important principle of film is "visual persistence". Scientific experiments show that after a certain visual image disappears, the human eye can still keep the image on the retina for about 0. 1-0.4 seconds. When the film rotates at a constant speed of 24 frames per second, a series of still pictures will produce continuous visual impression due to visual persistence, thus producing realistic motion.

1895, French brothers Auguste Lumière and Louis Lumiere developed a movable film machine based on Edison's film mirror and their own continuous camera.

Their film machine consists of a black box, which is equipped with a traction mechanism and a shading rotation mechanism for intermittent movement of 35 mm perforated film, and is equipped with a photographic lens and a projection lens.

With a camera lens, you can take pictures at the frequency of 12 frames per second and get the negative. Take off the camera lens, stick the exposed negative film with another unexposed film, and turn it into a positive film after exposure.

During the screening, the positive film is loaded into the machine. After the light bulb is lit, the light beam passes through the film and the lens, and the still picture passes through the film window at a very short interval at high speed, so that the image lingers on the retina of the viewer, and the viewer can see a group of moving pictures.