The Making of a Profile

Two of the printing industry's leading color management developers, RIT Research
Corporation (www.rc.rit.edu) and The Color Partnership (www.colorpar.com), together with
TRUMATCH, the 4-color standard for process color selection (www.trumatch.com), have
collaborated on a project to produce a "generic" 4-color press profile offered to Apple users at
no cost.

The introduction of ColorSync, as well as that of low cost color measurement devices, have
provided the catalyst for desktop color matching between all combinations of input, display
and output devices. ColorSync is a proven solution for device independent color
management, providing a path to ensure reliable and accurate color matching across devices.
It needs a scale however, a benchmark that says, "this is a reference point" - sort of a, "you
are here" statement. By creating a standard ("generic") profile, one that represents the
ultimate destination - a lithographic press - end users, software developers and hardware
manufacturers have a reference point on which to plot their courses.

The "generic" press profile on this CD provides users of Apple's ColorSync technology a
means of matching, on a desktop digital proofing system, the printed colors created by a 4-
color press. Using the ColorSync work flow with CMYK images, users can select the "generic"
press profile as the Source profile and the desktop printer's profile as the Destination profile.
This can be achieved using tools such as Apple's Photoshop Plug-ins to export images using
ColorSync profiles. Proofs created in this way on a CMYK desktop output device will more
reliably and accurately reflect the final printing characteristic of the press run, thereby
improving the reliability and accuracy of digital desktop printer proofs. Another good use of
the "generic" press profile is within a soft proofing application such as SoftProof from The
Color Partnership to view on screen how an image will appear printed to a 4-color press, and
make appropriate corrections, while comparing the color characteristics to those of a
desktop device.

To ensure the highest possible quality, The Color Partnership used Profile/80 - developed by
RIT Research Corporation (RITRC) - to create the ICC compliant profile for ColorSync 2.1.
RITRC is the research and development arm of the Rochester Institute of Technology (RIT).
RIT's School of Printing is one of the premiere teaching and research printing institutions in
the world while its Imaging Science program is #1 in the country. The science of color
printing has been a mainstay leadership technology of RIT for more than 60 years. Since
RITRC is not ordinarily in the business of commercial product marketing they contracted The
Color Partnership, for the publishing, sales, and marketing of Profile/80, because of its
recognized leadership in bringing color management solutions to market.

While Profile/80 is easy to use, it draws on years of color and printing research to create the
highest quality profiles possible for any output device, from desktop CMYK output devices to
high end 4-color process printing. Its intuitive interface allows even the most uninitiated
color user to create high quality profiles. The underlying spectral science in Profile/80 results
in smooth and accurate look-up tables while dealing with only 80 patches.

By using the specific characteristics of the various printing processes, many of them
pioneered by RIT, Profile/80 fits spectral data from just 80 color patches or references to a
deterministic model, creating look-up tables that are smoother than those of competing
products and therefore more reliable and accurate. Other applications use an empirical
approach, needing many more color patches to get a general idea of the characteristics of a
printer, then interpolating between those measurements to create a look-up table. In this
approach, the fewer the measurements, the weaker the look-up table and the poorer the
quality of the profile. As many as 1,000 patches may need to be measured to accurately
fingerprint an output device whereas Profile/80 can generate an equally accurate output
profile using the spectral data from as few as 80 color patches.

The use of spectral color data gives Profile/80 unique features such as patch averaging. This is
especially useful for profiling a 4-color printing press because the output pattern can be
reprinted both vertically and horizontally at different stages during the printing run and the
data averaged for a true "fingerprint" of the press. Profile/80 also allows the user to perform
single color profile updates, e.g if just the magenta ink is changed, only 24 patches need to
be read to update the profile.

To create a "generic" press profile, the 80 patch output pattern is printed to the exacting
standards required to print TRUMATCH Colorfinders. These are industry recognized reference
guide fanbooks for assigned-color selection. To print to these exacting levels additional on-press
targets or color bars are used, such as those from System Brunner. These proprietary
on-press targets are printed strips across the width of the printing form outside the image
area - usually on the trailing edge. The strips contain carefully designed repeat patterns of
single color solids, solid overprints, and dot gain targets. These strips are measured for ink
film thickness, dot gain and color balance by densitometry. Perceptual color variations in
printing are due primarily to shifts in dot gain, which can result in distinguishable
differences in color balance. Even small shifts in dot gain can result in distinguishable
differences in perceived color. This type of print measurement strip has also been adopted by
the general Requirements for Commercial Offset lithography (GRACoL) standards committee.

The Profile/80 output pattern is then measured using an X-Rite Digital Swatchbook
(www.x_rite.com) and a "generic" press profile created. This profile is a fingerprint of the
characteristics of the particular press used. Presses have different characteristics, even from
the same manufacturer, model, age etc. - the same as autos of the same manufacturer, model
and age differ. However, for this exercise the profile from a 4-color press can be considered
as generally representative of all 4-color offset presses.

The TRUMATCH Colorfinder is based upon a unique, patented system of organizing the CMYK
gamut according to hue/saturation/brightness. The TRUMATCH 4-color palette is an
established color standard, and is featured in all the leading software for design and
illustration from Adobe, Corel, Deneba, Macromedia, Quark. (See: www.trumatch.com/ or call
1-800-TRU-9100 for information and ordering.)

RIT Research Corporation also offers a service for custom profile making for those without
access to a color measurement device, called Profile-by-Mail. The service uses Profile/80
technology to generate a profile from the customer's printer. For more information on
Profile-by-Mail, go to www.rc.rit.edu/profile-by-mail.

For more information on, or to purchase your own copy of Profile/80, contact The Color
Partnership at info@colorpar.com or call us at 1-800-554-8688. Check our web site at
www.colorpar.com for more ColorSync tools available from The Color Partnership.


Macintosh, Mac OS and ColorSync are trademarks of Apple Computer, Inc., registered in the United States and other countries.