The sample is illuminated with the light beam directed at a given angle. The light reflected by the sample is measured by the photodetector, which is positioned at the same angle but on the opposite the light beam source.

Measuring unit: gloss unit (GU) or percentage (%)

Four versions are available:

1. TAPPI 20^o
2. TAPPI 75^o
3. DIN 45^o
4. DIN 75^o