Digitized typesetters set type with greater speed and detail than
electromechanical machines. An electronic beam draws on the face of the
CRT tube in random fashion. Image refresh is greater than 30 times per
second at 2,600 lines per inch (LPI).
Figure 4-7 shows character imagery in digital phototypesetting.
Figure 4-7. Digitized phototypesetting.
Light amplification by simulated emission of radiation (LASER)
phototypesetters raster scan an image in a very tight pattern with a narrow
beam of light or energy. This allows for precise control of the image area.
Characters, art, and halftones are generated picture element (PIXEL) by pixel
at 700 to 1,500 LPI. Point size ranges from 5 to 246 points. Note that a
point size and a pixel are not the same. Notice also that a halftone and a
pixel are not the same. A halftone is comprised of pixels and how many
depends on the resolution of the screen and the percentage of the halftone
pattern desired. This type of typesetter and processor is also known as a
raster image processor (RIP).
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