RU25: Problems with Colors - and the Solution: Color Management
The profession of the technical editor is rapidly
changing, from the pure text manufacturer to a
data manager, which leads inevitably to intensive
occupation with the production of the final
product: the technical documentation on paper
or online. The color matching reproduction on
the local screen or printer plays a new, important
role. Particularly since the meaning of color in
documents increases rapidly.
|
No Document Without Color
|
A multiplicity of reasons forces the editor to use
color in documents consistently. The advantages
in the efficiency of knowledge transfer from
author to reader are outlined in figure 1.
| Docoments in colour... |
|---|
...reduce mistakes (50%)
...improve understandability (73%
...improve learning capability and rememberence (55-78%)
...increase recognition (78%)
...increase motivation (80%)
...increase the willingness for reading(80%)
...sell better (50-85%)
|
Figure 1
Reasons for using color in documents
(after: Publishing Praxis/Tektronix)
|
Often a scan or a digital photo looks at the
monitor "beautifully multi-colored", but
unfortunately quite different from the original
photograph. With the printout on the color
printer or from the printing press one receives
even more unexpected color variations.
Often not only photos are concerned, but
frequently also computer-drawn diagrams and
illustrations. With "trial & error" one wastes
valuable time, until the company logo on an
overhead transparency at least comes close to the
corporate design guideline colors.
Increasingly, data from different sources are to be
linked as part of automated database publishing
systems. If superordinate systems do not provide
for color consistence, even color deviations are
difficult to avoid within one single document.
|
The Solution: Color Management
|
Color management is a technique that will
become generally accepted within the near
future in each communication area. Color
management systems achieve two substantial
targets:
- Color consistent representation of diagrams and
photographs, independent of the source and
the output device
- Exact color reproduction without any effort or
additional knowledge on color management by
the user
Color management takes up the problems from
two sides:
- Input and output devices, as well as monitors,
reproduce colors in a nonlinear manner,
depending on their physical concept or by
construction. Even two identical models from
the same manufacturer don't reproduce color in
exactly the same way. It is possible, however, to
locate the deviations by using suitable
measuring procedures, and to store these
device-dependent faults in standardized device
profiles (ICC profiles).
- The devices which are part of the document-creating
process operate based on different
physical concepts - from the standardized
printing inks of offset printing presses to the
CCD chips of the digital camera over the x-ray
tube of the color monitor. Each process has a
typical color space, whose representable colors
are limited and - of course - are not compatible
with color spaces of other devices within the
production chain. In the entire chain from the
camera to the printout the original color space
of the picture is inevitably reduced and cut
smaller and smaller.
Figure 2
RGB and CMYK color spaces as polygones
compared to the whole of all visible colors
(so-called shoe-sole)
Figure 2 shows all colors distinguishable by the
(average) human eye as a shoe-sole shaped area.
You can find, drawn in as a triangle, the
delimitation of the idealized RGB color space as
an example for scanners, digital cameras and tube
monitors with their three basic colors: red, green
and blue. The pentagonal area embedded into
the RGB triangle shows the idealized surface of
those colors, which remain after the CMYK
transformation - which color lasers, offset
printing machines and ink jet printers use.
Color management systems correct the device
errors behind the scene of the operating system
and execute the conversions of the colors
between the different color spaces in such a way
that the final result comes close to reality - with
consideration of physical boundaries.
|
Cost Efficiency of Color Management Systems
|
Color management systems, which include all
workstations that are part of the document
management process, offer the following
advantages:
- Higher efficiency during the creation of
documents by color consistency, without filling
wastebaskets with expensive misprints.
- Consumables can be saved - particularly by the
avoidance of expensive new exposures of offset
films and the appropriate proof prints.
- Expensive proof prints can be replaced by color
matching, low-priced soft proofs, which need
less time to produce.
- The creator of a document can concentrate on
contents; pedantic color corrections and
multiple printouts can be omitted.
- Time-critical printing productions can be
calculated better, since color problems can be
eliminated.
For the implementation of a color-management
system in terms of hardware, no investments are
necessary. The calibration of the critical input and
output devices and monitors is usually offered by
service bureaus as the most economical solution.
A prerequisite is, however, that the application
programs used are basically suitable for color-consistent
operation.
The training of the employees of a
documentation team is limited to minimum
procedures, since color management systems are
usually maintenance-free after the basic
installation.
Color management systems for color-consistent
monitor reproduction and for printing are
already economically applicable. However, even if
no major secrets are involved in implementing
and operating a color-management system, there
are nevertheless reasons why color-management
"by experience" is still used in many companies:
- The mechanism of a color management system
on the one hand makes color specialists
dispensable, on the other hand it requires
competent service bureaus, which are still quite
rare.
- Certain quality management procedures are to
be modified or even redefined, as far as
interfaces to typesetters, digital printers and
layout studios are concerned.
- There are technical restrictions: some
application programs still don't support color
management in a perfect way, or need
additional plug-ins or utilities to perform within
a color-management system.
However, color-management systems are in a
rapid development phase, so that solutions for
the remaining problems can be counted on
shortly.
- Agfa Deutschland: Die Geheimnisse des Farbmanagements.
- Die digitale Farbe Teil 5. 1997.
- FOGRA - Forschungsgesellschaft Druck e.V.
- http://www.fogra.org.
- Homann, J.-P.: Digitales Colormanagement.
Farbe in der Publishing-Praxis. Berlin u.a.
- Springer 2000 (x-media press).
- ICC - International Color Consortium
- http://www.color.org.
- Linotype CPS GmbH: CD PrintOpen ICC 3.0/
- color Management Books. 1997.
- Tektronix:
- http://www.colorize.com/learn
- Thiele, U./Kaffka, M.: Farbmanagement. Ein
Leitfaden für die praktische Anwendung.
- Reutlingen: doculine 2000.
- Thiele, Ulrich: Ergänzungen und Aktualisierungen
zum Farbmanagement:
- http://www.thiele-colorconsult.de.
© TC Forum 1998-2001 - http://www.tc-forum.org - file last updated 10 Dec 2000
"transline Deutschland - Übersetzungsdienst für technische Übersetzung"
Web design by "Alexander von Obert"
Readability/Usability/Quality
