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% Reflectance
Materials having a high refractive index such as clear plastics and varnishes can
typically have measurement values that exceed 100GU due to multiple reflections
occurring within the material. Highly reflective metals can also produce gloss values up
to 2000GU. In these cases, it is common not to report values in GU but to express them
in terms of percentage Reflectance.
% Reflectance therefore compares the amount of light energy transmitted and received
by a gloss meter and expresses the value as a percentage of the measurement angles
full range.
Whilst the Gloss (GU) scale is linear, each measurement angle has a different upper
range; 20°: 0 – 2000GU, 60°: 0 – 1000GU, 85°: 0 – 199GU.
The measurement mode is a simple conversion of gloss value to percentage
reflectance.
20 degree - 2000GU = 100% reflectance
60 degree - 1000GU = 100% reflectance
85 degree - 199GU = 100% reflectance
So, 20 degree - 1000GU = 50% reflectance, 500GU =25% etc
When the Novo-Gloss 20/60/85 with Haze is calibrated in this mode it will calibrate to
the GU value but will still display % reflectance.
