Film music is music that may be added to films in order to supply an "atmosphere", or to tell the audience something extra about what is happening on the screen. For example, a sudden and frightening event on the screen can be made all the more terrifying if accompanied by a sudden and frightening sound. A cleverly orchestrated chord can seem like a swipe over the head. Furthermore, it is perfectly possible for the music to contradict what is happening on the screen. For example, if the picture shows a quiet country lane and the director wants you to know that something unpleasant is about to happen, the music can suggest this feeling quite easily.
The importance of music was realised from the early days of film. In the silent film era, performances were accompanied by the piano, or in larger cinemas, by a small orchestra. The music was either made up on the spot by the pianist or selected from a library of suitable pieces.
Writing the film score
In writing a film score the composer can adopt two basic approaches. Either he can write music which suggests the general mood of each scene, or he can write music which underlines every detail of what is happening. If the composer takes the first line of approach all he needs to know is the length (in seconds) of each scene and what the mood is supposed to be. If he takes the second line, he will need to know not only the length of each scene, but the exact moment (to the split second) when each event occurs.
The composer will see the film several times and be given a detailed "cue sheet", showing each shot, its length and the exact moment when events take place. All this can be worked out to the split-second by counting the number of "frames" (each individual photo-picture) in each scene and working out a timing. The composer can then calculate how many bars of music he needs, what the music should be like and at exactly which bar his "musical event" will take place.