Oce VarioPrint i Series, Operation Manual

Page: 378 / 402

NOTE
• The |∆L| value refers to the
absolute
value of
△
L.
• The
weighted
|∆L| puts more emphasis on the colour differences for light greys, where the K
value is lower than 50%. (
△
L (Delta L) on page 263
)
• The Estimated black point |∆L| metric is called an
estimation because the darkest patch of the
target chart is not necessarily the darkest possible colour. There could be CMYK values that
reproduce a darker tint. The output profile determines the real black point value.
• Refer to
Patches of the target chart on page 259
to read the description of the patches.
△
Ch (Delta Ch)
Metrics Description
Average ∆Ch composite
grays Average colour difference in ∆Ch between measured Lab values of
the composite greys on the colour control strip and the Lab values of
the matching patches of the reference printing condition.
Maximum ∆Ch compo-
site grays Highest colour difference in ∆Ch between measured Lab values of
the composite greys on the colour control strip and the Lab values of
the matching patches of the reference printing condition.
Average weighted ∆Ch
composite grays Average colour difference in weighted ∆Ch between measured Lab
values of the composite greys on the colour control strip and the Lab
values of the matching patches of the reference printing condition.
Maximum weighted ∆Ch
composite grays Highest colour difference in weighted ∆Ch between measured Lab
values of the composite greys on the colour control strip and the Lab
values of the matching patches of the reference printing condition.
NOTE
• The weighted ∆Ch puts more emphasis on the colour differences between composite greys,
where C is lower than 50%. (
△
Ch (Delta Ch) on page 264
)
• Refer to
Patches of the target chart on page 259
to read the description of the patches.
Overview of colour validation metrics
378 Chapter 14 - References