HP RIP Software - HP RIP Software User Guide

Color Management Overview 4-5
b* values are yellowish and negative b* values are bluish. Lightness
varies in the vertical direction.
Why Color Management
is Needed
To match colors in printed output to those in scanned originals is not a
simple task because of a number of variable factors in the reproduction
chain:
• Different image-capturing devices generate different output values
when reading the same original.
• Adjustments to monitor controls cause wide color variations.
• Gamut differences between monitors and printing processes mean
that unprintable colors can be introduced during image retouching.
• Printing devices vary widely in color rendering due to ink and media
characteristics.
• Viewing proofs and printed matter under non-standard lighting con-
ditions introduces errors of judgment.
• Ink-based adjustments permit wide variations in ink densities.
Fig. 4-1. The CIE L*a*b* color space