Graphics Programs Reference
In-Depth Information
matically reads the entire chart unattended. The DTP-70 is able to accept
a sheet of patches as large as 8.86 inches wide and 15 inches long and
can read the entire IT8 chart in about three minutes. The paper can be
as thick as .014 inches. This unit has a user-selectable UV filter that can
be switched on and off, and this Spectrophotometer can average three
samples of measurements per patch.
Which Spectrophotometer to purchase obviously is based upon your
budget and what you want the unit to do for you. If speed is of impor-
tance, one of the semi- or fully automated Spectrophotometers will
be high on your list. The handheld scanning Spectrophotometers like the
Eye-One Pro or PULSE are fast but require user intervention. It can take
a few attempts at building a profile using such an instrument to get pro-
ficient scanning a row of patches. However, these units are on the lower
end of the affordability scale and provide a number of functions such as
spot readings. In the case of the Eye-One Pro, this instrument has the
ability to calibrate and profile a display system or a digital projector.
The next item to consider when purchasing a Spectrophotometer is
software support. Although the Spectrophotometer is usually the largest
expense of the color management packages, not all software products
interface with all hardware products. It's usually a good idea to decide
what Spectrophotometer is appropriate for your needs and budget and
ensure it will interface with the software you will purchase. The Spec-
troscan, Eye-One Pro, and DTP-41 are all very well-supported instru-
ments found in virtually all the major profile software products discussed
later.
Calibration and Printer Profiles
Some printers require regular calibration. Others are stable enough
whereby all we need to do is measure how they produce color. Printers
whose media are made in batches or emulsions that vary require a cali-
bration. This is to ensure the output is consistent. Whenever I place new
donor into my Fuji Pictrography 4500, I must print out a small target and
measure it with the built-in calibrator. This calibrator is in fact a densit-
ometer. However, this is all that's necessary to measure the target and
calibrate the printer back to factory specifications. This produces consis-
tent behavior and thus only one profile is necessary to describe the device
behavior. Any deviations in media are accounted for using this calibra-
tion process. When I replace one ink cartridge in my Epson 2200 with a
new ink cartridge, I don't have to do any calibration; I continue to print.
The device is reasonably stable and consistent and some are self-
calibrating. If you're willing, you can plot the consistency of a device's
behavior over time when building ICC profiles.
Prior to printing targets and conducting calibration (if available),
always ensure the printer is behaving optimally, as it should. For
example, if you are about to print a target on an ink-jet printer, be sure
