Glossmeters are used to measure the gloss of a surface and the measurement expressed as gloss units. A beam of light is projected at an angle onto a surface and then measured at an equal but opposite angle.
Depending on the type of surface being measured determines the angle used in the measuring process. Metal for example has a much higher rate of reflection which means it is less dependent on the angle of measurement.
Glossmeters are commonly used in the automotive industry to measure the gloss of paint finishes on vehicles.
There are three main measurement angles, these are 20°, 60°, and 85°. These angles cover most industrial coatings and materials. A gloss range decides what angle is going to be used for measurement.
A gloss unit is the standard of measurement used to determine the level of gloss on a surface. Highly polished black glass is used to determine 100GU which is the highest level of gloss. A perfectly matte surface is used to determine the 0GU measurement.
As well as gloss meters there are instruments to measure orange peel and haze. These are especially useful when comparing two surfaces which appear to have the same level of gloss but look very different. Orange peel especially can affect the visual appearance of a surface, but this can be measured by an instrument and a result displayed.
Overall there are professional instruments to measure all types of surfaces and any defects which may be on these.