How do I use a glossmeter to measure gloss?

What is a gloss meter?

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

Gloss Meter Selection

Identify the surface that you wish to measure.  Flat surfaces can be measured with a traditional handheld glossmeter.

If the surface is curved or the surface area to be measured is smaller than that of the measurement aperture of the gloss meter then  equipment, there are instruments specifically designed for these types of application. Both Benchtop and handheld instruments are available for these types of applications.

Selecting the correct gloss meter is dependent on both the application and level of gloss of the surface and each gloss meter specifies the measuring angles utilized.

Three main measurement angles (20°, 60°, and 85°) as discussed in ISO 2813 and ASTM D523 are specified to cover the majority of low gloss to mirror finish applications. Choose the angle of measurement based on the anticipated gloss range of your surface as shown:

Novo Gloss Gloss Meter Measuring Panel
Gloss Range 60° Value Notes
High Gloss >70 GU If measurement exceeds 70 GU at 60°, change test setup to 20°

Examples of high gloss finishes include:

High Gloss Finish on a New Car
High Gloss Finish on Polished Concrete
Polished Metal with a High Gloss Finish
Gloss Range 60° Value Notes
Medium Gloss 10 - 70 GU

Examples of medium gloss finishes include:

Modern kitchen interior 3d render - furniture with a medium gloss finish
Medium Gloss finish on Cartons and Packaging
Gloss Range 60° Value Notes
Low Gloss <10 GU If measurement is less than 10 GU, change test setup to 85°

Examples of low gloss finishes include:

Seamless linen canvas with a low gloss measurement
Carbon Fibre with Low Gloss
Leather is another example of a Low Gloss Finish

GU (Gloss Unit) is the measurement unit for gloss, the ranges are as followed:

20 degrees: 0-2000 GU (where 0 is matt and 2000 is a perfect mirror)

60 degrees: 0-1000 GU (where 0 is matt and 2000 is a perfect mirror)

85 degrees: 0-199 GU (where 0 is matt and 199 is a perfect mirror)

206085 gloss visual reprenstation

Selecting the correct angle for the application will optimize measurement accuracy.

Two variants of instruments are available from Rhopoint: 60° single angle instrument, triple angle instrument 20°, 60° and 85° the second giving improved accuracy of measurement for very high or very low gloss finishes.

Two additional angles are used for other materials. An instrument with the angle of 45° is specified for the measurement of the gloss of ceramics, films, textiles and anodized aluminium, whilst 75° is specified for paper.

If a the appearance of a high gloss surface is affected by other surface texture effects such as orange peel or a 'milky' finish or halos around reflections of bright light, these can be measured with the Rhopoint IQ