A glossmeter (also gloss meter) is an instrument which is used to measure specular reflection gloss of a surface. Gloss is determined by projecting a beam of light at a fixed intensity and angle onto a surface and measuring the amount of reflected li

A glossmeter (also gloss meter) is an instrument which is used to measure specular reflection gloss of a surface. Gloss is determined by projecting a beam of light at a fixed intensity and angle onto a surface and measuring the amount of reflected light at an equal but opposite angle.

 

The gloss meter provides a quantifiable way of measuring gloss intensity ensuring consistency of measurement by defining the precise illumination and viewing conditions.[6] The configuration of both illumination source and observation reception angles allows measurement over a small range of the overall reflection angle. The measurement results of a glossmeter are related to the amount of reflected light from a black glass standard with a defined refractive index. The ratio of reflected to incident light for the specimen, compared to the ratio for the gloss standard, is recorded as gloss units (GU).

 

Measurement angle refers to the angle between the incident light and the perpendicular. Three measurement angles (20°, 60°, and 85°) are specified to cover the majority of industrial coatings applications. The angle is selected based on the anticipated gloss range, as shown in the following table.

 

Gloss meter

Gloss Range	60° Value	Measure with	Notes
High Gloss	>70 GU	20°	If measurement exceeds 70 GU, change test setup to 20°
Medium Gloss	10 - 70 GU	60°	/
Low Gloss	<10 GU	85°	If measurement is less than 10 GU, change test setup to 85°

 

 

 

For example, if the measurement made at 60° is greater than 70 GU, the measurement angle should be changed to 20° to optimise measurement accuracy. Three types of instruments are available on the market: 60° single angle instruments, a combination of 20° and 60° and one type that combines 20°, 60° and 85°.