Figure 5-2. SlideWriter Imaging Process
The SlideWriter's microprocessor decodes input data received from
the host through an SCSI interface cable and controls the CRT beam
path and intensity. The CRT produces up to 256 different shades of
gray which, when combined after the three color passes, can
produce a maximum of 16.7 million colors.
The microprocessor rotates the filter wheel, controls the camera
shutter, and advances the film. The display control indicates
information on the Display Panel and accepts operator input via its
panel switches.
The CRT images the computer-generated data in the form of a
traveling spot of light. The filter wheel electronically selects the color
filter that the light will pass through and a lens focuses the light on
the film. The shutter in the film back opens to allow film exposure.
Images are created by exposing the film to each resolvable location
along the scan line for the amount of time per color as specified by
the incoming data.
After completing a color pass, the filter wheel rotates and the
process repeats until each of the three primary colors (red, green,
and blue) has been recorded.
The SlideWriter digital film recorder utilizes a time-modulated film
recording process. This means that the light intensity of the CRT's
electron beam remains constant for each pixel exposure while the
amount of time spent on recording each pixel varies. The result is
very consistent spot size and color balance.
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