Measurement Function D - Techkon DENS Manual

1
K C M Y SLUR C+M
Measurement on a gray balance patch:
Rolling display of the single CMYK values one
step every second.
A gray balance patch is composed of different
portions of Cyan, Magenta and Yellow. It does
not include black ink.
2.2 Measurement function D %: Dot area measurement
in reflection
For the function Dot Area (= dot percentage) two measurements have to be carried
out. First a measurement on a solid patch and then a measurement on a %-patch
(= screen patch). The dot area value is calculated with the Murray-Davies formula.
C M Y BAL S/D C+M K
1. Measurement 2. Measurement
2
K C M Y 80% 40% BAL
C M Y BAL 80% 40% 0
CHAPTER 2
– Measurement functions
When making a measurement on a gray bal-
ance patch, the referring density values for all
four process colors are shown. The values for
Cyan, Magenta and Yellow should be in close
range to each other to ensure a neutral gray
balance without a color hue.
It is important that the gray balance patch, on
which the measurement is taken, comprises
the right %-values to achieve a neutral gray
when printed correctly. The process standard
ISO 12647 for offset print defines the values as:
C = 50 %,
M = 40 % and
Y = 40 %.
The value for Black indicates how dark the
gray color is. The higher the value for Black
(= K) the darker the sample.
To capture the dot area in %, first the solid
density patch of the color has to be measured.
1. Place the measurement head above a solid
patch and start the measurement by pressing
the DENS button. The solid density value will
be displayed.
2. Now make a second measurement on a %
patch and the dot area in % will be shown.
In this case a measurement has been taken on
solid density and a 80 %-patch of Cyan. The
effective dot area is 93.4 %.
The resulting dot gain can be easily calcu-
lated: 93.4 % - 80 % = 13.4 %
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