A Film Does Not Exist

The lights in a cinema theatre grow dimmer. Talking dies down and people rustle their bags of sweet to get them opened. The film begins. For a moment, the film takes the viewer away from everyday life to an imaginary world. The experience is so powerful that when the film ends, it takes a while to recover.

What is a cinematic experience made up of then? Several researchers have studied the subject of a cinematic experience, but its origins are still unclear. A cinematic experience is caused by perceiving a movement. The illusion created by movements is the result of the interaction between eyes, brain, and the mechanical structure of a film projector. The movement seen from the successive still pictures is not real, instead it is only a supposed image or a fantasy made by your brain.

According to Henry Bacon, a researcher in the Finnish Film Archives, a film is an optical illusion. Although we know that a movement is made up of a series of individual pictures, we cannot help perceiving the movement. Thus, in technical sense, a film does not exist, since it is only an illusion produced by our brain. The film moves past the lens at a very high speed. However, that is not enough to create an image of movement. For this reason, between the film and the lens there is a shutter that flutters 25 times per second. This makes us see the series of pictures as a movement.

Afterimage Does Not Explain the Experience

As late as in the 1970s the experience of movement was explained by the concept of the so called afterimage. It was thought that the illusion of movement is formed when the seen picture stays on the retina for a while after leaving the visual field. When shown fast enough, the afterimages seen one after another create an illusion of movement. It was assumed that an afterimage conveys the breaks between individual pictures on the filmstrip. However, seeing movements on the screen at cinema cannot apparently be based on this, because the afterimage lasts longer than 1/24 seconds. Therefore it should actually disturb seeing the continuous movement, explains Jukka Partanen, a social psychologist from the University of Tampere.

According to modern perceptual psychology, the illusory movement created by films can be explained by the phenomenon called Phi, which means the combination formed by flashing and covering the light. The phenomenon is based on the fact that when two adjacent lights are turned on and off at certain intervals, viewers cannot see two separate lights, instead they perceive only one moving light. If the projected light flashes fast enough, the blinking will be seen as a single continuous light. On the other hand, the covering of the light is based on the fact that viewers need certain time in order to sense the impulse. When an image is rapidly replaced by another, the earlier form is remembered. Thus, the series of images that is shown fast enough will be perceived as one clear and continuous vision.

The Phi-phenomenon, the flashing and covering of the light can work only when the film is projected so that 12-24 pictures of the filmstrip per second move past the lens. The individual pictures are normally lighted at the speed of 24 pictures per second. This is because the film will look a bit jerky, if the speed is any lower, such as 15 pictures per second.

Experience is More Than Just Perceiving Movement

Partanen has one more possible theory for perceiving movement. He uses the so called gedanken-experiment as an example. Let's imagine that we are filming a man walking across the room. We will cut every second picture off from that filmstrip, and put them together to form another filmstrip. Now we have two films that do not contain any pictures that are the same.

Next these two films are shown to the test subjects. After watching them, the subjects suppose having seen one single film twice. Despite the fact that they had neither seen any pictures that are exactly the same, nor had any sense perception of the same kind, they had seen precisely the same course of events. Thus, seeing events is not the same as a series of pictures or successive phenomena. It is a question about the information received from the change in optical structure, which analyses movements.

However, it is not possible to simplify a cinema experience to be a mere phenomenon on the retina and in the brain. Nobody watches films only by passively observing different series of movements. At its best, a film is a system that stimulates imagination and intelligence through senses. A film does not contain any meaning until the viewers interpret it through their own experiences and cultural backgrounds. A film does not exist without viewers, experiencers and culture.

Read more
Mind-enticing films (FN 2004 / saturday )