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CHAPTER 2
– Measurement functions
OBA amount
no OBA
faint
low
moderate
high
∆B
0 to 1
1 to 4
4 to 8
8 to 14
14 to 25*
∆CIEb*
0
-0,3 to -2,0
-2,0 to -3,7
-3,7 to -6,2
-6,2 to -10,4*
OBA-Check
Optical Brightening Agents (= OBAs) which are used more and more in the paper pro-
duction, have a significant effect not only on how we perceive the paper under dif-
ferent illuminants, but also on the results of the printing process. The measurement
function
OBA-Check
provides precise information about the intensity of the optical
brightening agents used and the shade of the paper.
Choose the function
OBA-Check
from the
menu measurement functions.
First you have to switch to the „soft-key“
CAL
to carry out a calibration on the absolute
white standard.
SpectroDens performs the
OBA-Check
ap-
plying the measurement conditions M1 and
M2, i. e. with and without stimulation through
UV light (see p. 50). The difference between
the two CIEb*-values leads to the final mea-
surement result.
The amount of optical brightening agents
according to ∆B (ISO 15397) and its categori-
zation according to ISO 12647-2:
(0 ≤ ∆B < 1)
no OBA
(0 ≤ ∆B < 4)
OBA faint
(4 ≤ ∆B < 8)
OBA low
(8 ≤ ∆B < 14)
OBA moderate
(14 ≤ ∆B < 25*)
OBA high
The table shows the relation between ∆B-
and CIEb*-values for the practical application.
* and beyond
