7
7
7
7
Reflected light sources in surfaces with medium and high haze values.
Coatings without haze can be seen to have a deep reflection and have high
reflected contrast. Those with a lower level of reflection haze exhibit a slight
“milky” finish which can be seen at the surface.
When viewing the reflection of a strong light source in a surface with high haze the
image “blooms” and has a bright halo around it.
Haze is an important measure for highly polished metals and is often associated
with polishing marks and machining direction.
Gloss-haze meters are traditionally used to measure this parameter and use a
standard glossmeter design with additional light stops and diodes to measure the
haze component 2⁰ either side of the specular.
Gloss-haze instruments have not found mainstream acceptance in the coating
industry because to take repeatable measurements the sample surface needs to
be completely flat and un-textured. The relative high cost of these instruments has
also been found to be prohibitive.
Measuring Haze with the Novo-Gloss IQ
The Novo-Gloss IQ automatically compensates for sample surface flatness and
texturing allowing haze measurements to be taken on most product surfaces.
Gloss Haze values are calculated using the angular tolerances described in ASTM
E430. The instrument can display the natural haze value (HU) or Log Haze Value
(HU
LOG
). When measuring haze values, higher numbers indicate a lower quality
surface. A high gloss surface with zero haze has a deep reflection image with high
contrast.
Log Haze Values are commonly quoted for paints and coatings as this scale has
increased resolution at the haze levels commonly seen on this type of surface.