User`s guide

B-5Kodak Color Matching System
This technology adds significant improvement in the quality and performance of the Color Manage-
ment System.
Note: You use the Source/Destination information when you setup or use your CMS-based applica-
tion, such as PageMaker 6.5.
Controlling UCR & GCR
Controlling UCR and GCR with Professional CMYK Profiles
In the final stages of color prepress production, the issues change: And your role changes with them.
You become that of a professional separator. And it becomes a question of how skilled you are at
making good films, films that run correctly on press, avoiding downtime, rework, and expense.
Kodak Digital Science Professional CMYK Profiles helps you with your separations. It expands
your selection of undercolor removal (UCR) and gray component replacement (GCR) options, so
you can produce correct, quality separations.
Some Background
It is difficult to print four wet layers of ink on top of one another. This is one of the physical
constraints of the printing process.
In theory, if you printed a 100% of each CMYK layer, you would have 400% Total Area Coverage
(TAC). Real-world experience proves this to be impractical. It is difficult to print jobs that have
more than 340% TAC, and most printers feel more comfortable with 280% TAC.
Another area of practical concern is in how process inks are combined. Most printers can not
produce a clear, dense black from cyan, magenta, and yellow. Black is needed to produce better
details, contrast, and to get a desirable density. Adding black to CMY reduces ink coverage TAC,
and thus improves the ability of paper to firmly hold each layer of wet ink, known as ink trapping.
So, from the concerns about ink coverage and ink combinations have come tried-and-true ap-
proaches to producing excellent films for excellent separations.
Two aspects of the offset printing process are undercolor removal (UCR) and gray component
replacement (GCR).
UCR
Undercolor removal is the practice of removing quantities of yellow, magenta, and cyan ink from
the dark neutral areas in a reproduction and replacing what was removed with an appropriate
amount of black. Kodak implements UCR in its Color Profiles within a TAC constraint: CMY gets
replaced by the maximum amount of K up to the TAC limit—so you get the highest possible
density.