Digital Prints

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Mastering Digital Printing
Linearization
Linearization (sometimes called optimization) is related to and is a type of printer calibration.
A theoretically perfect printer should be able to take any input value—say 50% black—and print it out with that exact same density on the
paper. Unfortunately, due to something called dot gain, and also because printers aren’t always perfect, or they may have been perfect at one point
but have now drifted off course, that 50%
black may be printing at the equivalent of
54% black. Multiply this by every percentage
and every color combination, and you
can see where having this kind of “nonlinear”
response undermines the whole
concept of accurate color printing.
One solution is to linearize the printer periodically
so that a 50% value will end up
50% on the paper. Many RIPs support linearization
(see image).
Printer Profiling
Once a printer is calibrated (or you’ve decided it’s stable and printing consistently enough),
you can characterize or profile it. In a color-managed workflow, this is where output device
or printer profiles come into play. Compared to monitor profiling, you’re dealing with an
even wider range of variables with printers. Fortunately, all these variables are taken into
account by printing and then measuring targets with an instrument and creating ICC profiles
from those measurements (see Figure 4.10).
ErgoSoft’s StudioPrint 10 RIP
performs a linearization step in its
“calibration” process when it has you
print out a Density Target and
instrument measure it. Shown is the
Target Measurement Window with a
graphic representation of the printer’s
density curve from which a final
calibration or “density adjustment” is
made by the RIP to adjust input-tooutput
values.
Courtesy of Amadou Diallo
www.diallophotography.com
Figure 4.10 To profile a color printer, first print the color management target, then measure the target using a device connected to the color profiling package to create
an ICC profile. Popular instruments for profiling include the ColorVision SpectroPRO spectrocolorimeter (left) and the X-Rite DTP41 spectrophotometer.
Courtesy of ColorVision, Inc. and X-Rite, Inc.