248
Graphic Communications
Copyright Goodheart-Willcox Co., Inc.
Colorimeters
Colorimeters measure and compute XYZ color
values in a way that models vision. The results are
usually reported in a CIE color space. Colorimeters
record all visible colors, but generally are not as
precise as densitometers or spectrophotometers.
Two types of colorimeters are the trichromatic
colorimeter and the monochromatic colorimeter.
Used for quality control and calibration,
colorimeters are effective at measuring color and
creating profiles to ensure color accuracy across a
range of electronic devices, such as your monitor,
printer, projector, and camera.
A trichromatic colorimeter allows the user to r
match a patch of light by combination of the three
primary colors. Even though this instrument relies
on the perception of the eye, it is a useful device for
color measurement.
A monochromatic colorimeter does not r
measure types of color, but measures the intensity
of a particular color. Unlike the trichromatic
colorimeter, it does not depend on the perception of t
color by the eye.
Spectrodensitometers
Spectrodensitometers serve all the functions
of a spectrophotometer, densitometer, and
colorimeter in a single instrument. In addition to
measuring color value and optical density, including
ink density, dot gain, and dot, they also measure
paper attributes and special colors.
Computer-to-plate technology now requires
a tool to read the microscopic details on the
plate substrate. These spectrodensitometers use
powerful graphic signal processors for imaging. See
Figure 11-27.
The Human Visual
System
A photomechanical reaction that occurs in the
eye when light stimulates retinal receptors allows
us to see. The retinal receptors supply electrical
impulse patterns to the brain. Images are formed
in the mind and take on meaning for the viewer.
Career
Link
Color Specialist
A high percentage of the jobs that are printed today
have some color as a part of the finished product.
The customers know what they want or like. When
someone says the red is not red enough, the color
specialist must work with that customer to meet the
needs so the images are accepted. Customer approval
of color images is a very critical step in the process of
creating the finished printed product.
The color specialist must be an expert in
understanding color theory. The end results of
the specialist’s work must ensure accurate color
reproduction. Therefore, the color specialist must
be competent in working with color calibrations,
color separations, and color management. This
expertise requires the application of color to types
of media as well as to all printing processes. The
ability to communicate clearly with customers and
technicians is imperative. This person must be able
to process, comprehend, and follow detailed written
and verbal instructions.
A college education degree in graphic
communications is recommended. Experience in
the prepress area is imperative. Many of the high-
quality printers require that the color specialist be
a G7 certified GRACoL expert. The G7 certification
is a way of defining visual appearance. Belonging
to this group classifies the specialist as an elite
professional.
“Starting in 2000, the full-sized heatset web-fed
presses were able to upgrade to closed loop color,
presetting of inks, and registration that really worked.”
Pam Carritt
Courier Graphics Corporation