EFI DocuColor 5252 Supplementary Manual page 56

C 56
ALIBRATION
Success in obtaining satisfactory print quality from the Fiery EXP6000/EXP5000 depends on
many factors. Among the most important are establishing and maintaining optimal toner
densities. The density is the measure of the light absorbed by a surface. By carefully regulating
toner densities, you obtain consistent printed color.
Even with a calibrated system, toner density is affected by the settings of digital press,
humidity, and temperature. Density also tends to drift over time. Uneven toner density on
paper affects calibration results. Regular measurement detects day-to-day variations in density,
gradation, and color reproduction, and calibration corrects them.
Calibration works by creating calibration curves on the Fiery EXP6000/EXP5000 that
compensate for the difference between actual (measured) and desired (target) density values.
These calibration curves are the graphic equivalent of transfer functions, which are
mathematical descriptions of changes that are made to the initial data. Transfer functions are
often graphed as input or output curves.
The Fiery EXP6000/EXP5000 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.
Measurements
Measurement files contain numerical values that correspond to the toner density produced by
the digital press when it prints solid cyan, magenta, yellow, and black, and graduated tints of
those colors.
To create a measurement file, print a page of color patches. Measure the patches using a color
measurement instrument connected to a computer on the network. The new measurements
are automatically downloaded to the Fiery EXP6000/EXP5000.
Output profiles and calibration sets
Output profiles and calibration sets define desired calibration results. One or more output
profiles and calibration sets are provided with the Fiery EXP6000/EXP5000. When you
calibrate the Fiery EXP6000/EXP5000, select the calibration set that corresponds to the
typical printing jobs at your site. This same calibration set can be associated with one or more
output profiles. For more information about output profiles, see page 63.