Oce VarioPrint i Series, Operation Manual

Page: 259 / 402

Patches of the target chart
The patches of the target charts represent primary colours, secondary colours, greys and other
colour mixes. The following patch names are part of the metrics that are part of the tests.
Example Description
A
composite grey patch
is a patch where K ink is not used. Instead,
Y, M and C are used to darken the colours. M and Y have the same
value. C has the largest value, but the difference is not more than
17%.
An
RGB overprint patch
is a patch where equal amounts of two inks
are used: Y and M, Y and C, C and M. The inks are printed in one
patch to produce R, G or B.
A
K-only patch
is a patch where only K ink is printed.
The darkest patch is the patch which corresponds with the estima-
ted black point. The black point is the Lab value with the lowest L*
value.
A solid patch is a patch printed with 100% C, M, Y or K.
Tolerance levels
The difference between two colours or two groups of colours can be expressed by a colour
metric. (
Learn about colour differences on page 261 )
Every test definition has a pre-defined series of colour metrics ( Overview of colour validation
metrics on page 375 ) The test definition also includes for every metric a tolerance level to decide
if printed colour values are close enough to their reference colour values. A tolerance level or
threshold level is set before the evaluation takes place. A tolerance level is also expressed by a
△
(Delta) value. Based on the test outcome, a quality level can be achieved.
Test results
PRISMAsync Print Server shows the main results in the feedback window and lists all test details
in a CGATS report. (
Read colour validation results on page 270
)
The following example is not based on a realistic printer and print environment.
Learn about colour validation tests
Chapter 10 - Print what you expect 259