Printing Techniques; Halftone And Continuous Tone Devices - Xerox Fiery color server User Manual

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A-9 Desktop Color Primer
The CMYK colorants used in offset printing and by your printer toner are to some
degree transparent. When one layer of colorant is applied on top of another, you see
the effect of both. To create a range of intermediary colors, a method is required for
varying the amount of each colorant that is applied. A technique called
used in offset printing, while color printers typically use a proprietary system for
applying ink or toner colors that is similar to halftoning.

Printing techniques

Until recently, most color printing was done on printing presses using one of several
printing techniques—offset
traditional printing techniques require lengthy preparation before a press run can take
place. Short-run color printing, including Color Server printing, eliminates most of
this preparation. By streamlining the process of color printing, the Color Server makes
short print runs economically feasible.
In contemporary offset lithographic printing, digital files from desktop computers are
output to an imagesetter, which creates film separations. The film is used to make a
prepress proof, which is an accurate predictor of the final print job and allows you to
make corrections before going to press. Once the proof is approved, the printer makes
plates from the film and runs the print job on the press.
With the Color Server, you simply print the file. The Color Server processes the
PostScript information in the file and sends four
magenta, yellow, and black) to the printer. The ease of Color Server printing makes
possible experimentation that would be too costly on a press, allowing unlimited fine-
tuning of color and design elements.

Halftone and continuous tone devices

Halftoning is used in offset printing to print each process color at a different intensity,
allowing millions of different colors to be reproduced using only the four process
colors. Depending on the required intensity of a given color, toner is placed on paper
in dots of different size. The grid of dots used for each toner color is called a screen.
Halftone screens are aligned to unique angles designed to eliminate interference
patterns called
lithography, flexography, or gravure, to name a few. All
moiré that can arise with halftoning.
halftoning
bitmaps (one each for cyan,
is