Film recorder
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A film recorder is a graphical output device for transferring digital images to photographic film.
The simplest film recorders typically work by displaying the image on a grayscale cathode ray tube (CRT) placed in front of a photographic camera.
For color images, the red, green, and blue channels are separately displayed on the same grayscale CRT, and exposed to the same piece of film through a filter of the appropriate color. (This approach yields better resolution and color quality than one could obtain with a color CRT.) The three filters are usually mounted on a motor-driven wheel. The filter wheel, as well as the camera's shutter, aperture, and film motion mechanism are usually controlled by the recorder's electronics and/or the driving software.
Higher-quality film recorders use lasers to write the image directly onto the film, one pixel at a time. This method is better suited to large-format media such as poster-size prints.
In any case, the exposed film is developed and printed by regular photographic chemical processing. Self-developing (Polaroid) film can be used for immediate feedback.
Formats
Film recorders are (or were) available for a variety of film types and formats.The 35mm negative film and transparencies are popular because they can be processed by any photo shop. Single-image 4x5 film is often used for high-quality printing.
Some models have detachable film holders to handle multiple formats with the same camera.
Uses
Film recorders are used in digital printing to generate master negatives for offset and other bulk printing processes. They are also used to produce the master copies of movies that use computer animation or other special effects based on digital image processing.
For preview, archiving, and small-volume reproduction, film recorders have been rendered obsolete by modern printers that produce photographic-quality hardcopies directly on plain paper.
Film recorders were also commonly used to produce slides for slide projectors; but this need is now largely met by video projectors that project images straight from a computer to a screen.
Film recorders were among the earliest computer graphics output devices. See, for example: IBM 740