Projector
|
| 35 mm slide projector by the British Aldis company. image by S. Erik Bjernhage (Image rights) |
A projector is a device that focuses an enlarged image from a piece of film (almost always a positive image, often mounted as an individual 'slide') onto a screen for viewing. It is very similar in principle to an enlarger, comprising a light source, film holder, and a lens with a focusing mechanism; however, the arrangement of these components is somewhat different because images are usually projected horizontally, and because of the different scale usually required; it is usual to project images for viewing at large degrees of enlargement, and the screen is likely to be a long distance from the projector. In addition to the basic components listed above, a projector is likely to have a mechanism for changing from one slide to another, and a cooling fan to protect the film from the lamp's heat.
A projector is also the corresponding device for showing cine film.
