Techkon SpectroDens Manual page 47

By measuring the trapping only the variation
from the reference will be displayed.
The ISO standards define no tolerances for
trapping, only informative reference values
are given.
But it is recommended, not to exceed a ∆E*-
value of 10 in the secondary colors, which
corresponds with the sum of the permitted
∆E*-deviations of the primary colors.
Manual TECHKON SpectroDens Chapter 2 – Measurement functions Page 47