Glossiness is a physical quantity that evaluates the ability of a material's surface to reflect light. As a surface characteristic of an object, gloss depends on the specular reflection ability of the surface to light. Specular reflection refers to the reflection phenomenon that the Angle of reflection is equal to the Angle of incident. Glossiness is a physical quantity that evaluates the ability of a material surface to reflect light under a set of geometrically specified conditions. Therefore, it expresses the property of reflection with directional selection. According to the characteristics of gloss, gloss can be divided into several categories. We usually say gloss refers to "mirror gloss", so gloss meter, sometimes also called mirror gloss meter.
Glossiness is measured based on the amount of light reflected off the surface relative to the polished glass reference standard. The amount of light reflected off a surface depends on the Angle of incidence and the nature of the surface. The unit measure of gloss is a gloss unit(GU). The lower the GU, the less gloss reflection. The higher the GU, the higher the reflected gloss.
The gloss is divided into matte, semi-gloss and high gloss finishes. The measured Angle is the Angle between the incident light and the reflected light. Three measurement angles (20º/60º/85º) are specified for covering most industrial coating applications. To determine or select the right Angle to meet your needs, use a glossometer to measure the Angle at 60º and select the Angle within the desired glossiness range.