ALTANA Micro-TRI-Gloss μ - Manual (Page 51)

50
English
17 Practical measuring suggestions
In accordance with the standard,
the reflectometer value is related to
a black glass standard at a defined
index of refraction (generally
1.567) which is thus equal to 100
units.
Reflectometers are differentiated
by the angle of incidence of the
illuminating mechanism.
Geometries are set in the
standards at 20°, 60° and 85°.
Paints and varnishes, plastics
and similar materials
The various geometries are
distinguished according to their
fields of application as follows:
Semi-gloss surfaces are measured
at an angle of incidence of 60° and
should fall within a range from 10
to 70 gloss units.
Highly reflective surfaces with
measurement values exceeding 70
units in the 60° geometry should
be measured at 20°.
On the other hand, matte surfaces
with less than 10 gloss units (at
60°) should be measured at the 85°
geometry.