Film technology

Film is the most popular form of entertainment in the world, which makes use of the phenomenon of human visual persistence. Because human vision has the function of short-term memory, it can connect images displayed quickly and continuously. If the shapes and positions of the images are slightly different and displayed in front of people at a speed of more than 6 frames per second, the human eye will see a group of moving images. It is precisely because of this phenomenon of visual persistence that the foundation for the emergence and existence of our film industry today has been formed.

British doctor Paris first revealed this phenomenon. He drew a bird on the front and a birdcage on the back with a piece of cardboard. When the card rotates quickly, the two images overlap, making people see the bird as if it were in a cage.

However, the real principle of cinematography was invented by an Englishman, McBride. In 1872, in order to prove the state of four hooves when a horse is running, mcbride adopted 24 cameras arranged horizontally on one side of the runway, and the shutter of each camera was tied with wires and pulled on the runway. When the horse ran past the position of each camera, the line was broken to expose the camera. Thereby recording the shape of the moving horse and creating a new milestone for the development of film shooting technology.

McBride also invented a continuous slide projector to reproduce the photos he took. First of all, he developed and printed the photos one by one on a rotatable glass plate, and cooperated with a disc with a notch to separate the photos. The pictures appeared in the slot in turn, and each group of photos was irradiated by a hydrogen and oxygen spotlight in turn, and then projected onto the screen continuously, so that people could see the images in continuous motion.

1882, under the guidance of McBride, French scientist Mary also began to explore the photography skills of recording dynamics. In the same year, a photographic gun using a photosensitive glass plate was developed. The camera gun can take 12 photos per minute, and the exposure time is about 1/720 seconds. Five years later, Marley designed a film camera gun. He used a few meters of paper tape coated with photosensitive agent to pass it through the focus of the lens. Two hooks in the camera gun fixed the paper tape and exposed the frame in turn. Soon, Huysmans invented celluloid film instead of paper roll. Subsequently, Marley improved his camera gun so that it can shoot at 60 frames per second on 9 mm wide film. 1890, Marley obtained the patent of dynamic camera. 1893, he developed a projector based on plastic film and obtained a patent. His two inventions became pioneers of modern film equipment.

At the same time, Edison was also thinking about inventing movies. As early as 1885, shortly after Goodwin invented celluloid film in the United States, Edison thought of making movies with this film. He first made a camera, which can take action pictures for one minute with film. The basic principle is basically the same as that of the current camera. 1894, he invented a mobile viewing machine for showing pictures. This machine is like a cabinet, with a magnifying glass and a pulley, and there is about 50 feet of film in it. Put in a coin to start the motor, and watch it for about half a minute alone. 1896, he used the phonograph to add sound and music to his mobile viewing machine.

Since then, dozens of inventors around the world have made unremitting efforts for the invention of the film, but the final winner is the French Roumier brothers. The two brothers filled in the last brick on the building built by a large number of senior scientists. 1895 In February, the Rumir brothers applied for a patent for their invention of "continuous photography and projector". 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. When 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 pictures pass through the film window in turn at a very short interval, so that the image temporarily stays on the retina of the viewer, and the viewer can see a group of moving pictures. 1895, 1895 On February 28th, 1995, the two brothers sold tickets to show the film in a cafe in Paris, and finally put it into practical use. Although the film is still silent at this time, the camera and projector of the film are all ready, and the modern film equipment is finally completed. Since then, people all over the world have continued to engage in film research. 1905, German Rumohr successfully solved the problem of acousto-optic signal conversion, which can convert sound into light and record it on film. 1906, the French roster can record sound directly on film, and its principle is almost the same as that of today's audio movies. However, the talking movie was finally succeeded by American Fres. He applied electronics to the recording equipment of talking movies, and made the recorded movies come out in 1923. Recording film is to turn sound into light intensity, and form a change of light and shade on the film. Another is to turn the change of sound waves into the vibration of light and print the waveform of light on film.