Xerox Phaser 790, Documentation

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22. Using ColorWise Pro Tools
Xerox Phaser 790 22–2
Changing calibration has the potential to affect all jobs for all users, so you may
want to limit the number of people authorized to perform calibration. An
Administrator password can be set from the Fiery Control Panel or in Setup
from the command workstation to control access to calibration.
Understanding Calibration
Although most users needs are met by the default calibration set, the Fiery
allows you to choose a calibration set to customize calibration for specialized
jobs.
Calibration allows you to:
•
Maximize the color reproduction capabilities of the Fiery.
•
Ensure consistent color quality over time
•
Produce consistent output across Fiery servers that are connected to the
same print engine.
•
Achieve better color matches when reproducing spot colors such as
PANTONE colors or other named color systems.
•
Optimize the fiery for using ColorWise rendering styles (CRDs) and
CMYK simulations, and for using ICC profiles.
How Calibration Works
Success in obtaining satisfactory print quality from a color server, such as a
Fiery connected to a printer, depends on many factors. Among the most
important are establishing and maintaining optimal toner densities. Density is
a measure of the light absorbed by a surface. By carefully regulating toner
densities, you can obtain consistent printed color.
Even with a calibrated system, toner density is affected by service settings,
humidity, and temperature; it also tends to drift over time. Regular
measurement detects day to day variations in densities, and calibration
corrects for them.
Calibration works by creating calibration curves on the Fiery that compensate
for the difference between actual (measured) and desired (target) density
values.
Calibration curves are the graphic equivalent of transfer functions, which are
mathematical descriptions of changes that will be made to the data you start
with. Transfer functions are often graphed as input or output curves.
The Fiery generates calibration curves after comparing measured values to
the final target values for each of the four toner colors. The target values are
based on the output profile specified.