Describing how glossy a surface is, such as car paint or the trim on a house, can be very difficult to convey for the average person. The glossiness or shininess of an object is described using human perception; which is subjective and can be different from person to person. Yet, the general public has an understanding in their mind of what a high-gloss paint looks like and how it differs from a low gloss or matte paint. In order for manufacturers to understand how glossy their paints and coatings are, several test methods have been developed over the years which aim to define what gloss is and how to quantify it.
The most common method involves understanding how white light interacts and reflects from the surface of interest, and it is this method employed by Ebatco’s newly acquired Micro-Tri-Gloss meter. The Micro-Tri-Gloss meter (manufactured by BYK-Gardner GmbH), is a handheld instrument that can measure the glossiness of a surface. The Micro-Tri-Gloss meter is ideally suited for testing polymeric materials and paints (such as clear coats, house paints, etc.); but some ceramics or anodized metals surfaces can also be analyzed.
The gloss meter works by directing white light from a source towards the sample surface at a specific angle of incidence. A detector is positioned at the specular reflection angle for the incident light and it measures the light intensity of the reflected light. By comparing the light intensity of the reflected light and the light intensity from the source, the glossiness of the surface can be quantified in terms of Gloss Units, (or GU’s).
Typical Experimental Results
Applications
Annodized Surfaces | Automotive | Ceramics | Clear Coat |
Consumer Goods | Defect Analysis | High Gloss Paints | Industrial Coatings |
Matte Paints | Metals | Plastics | Privacy Screens |
Reflectivity | Residential Coatings | Satin Paints | Semi-Gloss Paints |
Surface Finish | Surface Roughness | Varnish | Weathering |
Instrument: BYK Micro Tri-Gloss meter
Key Specs
Measurement Geometries | 20°, 60°, 85° |
Measurement Range | 20°: 0 – 2000 GU 60°: 0 – 1000 GU 85°: 0 – 160 GU |
Measurement Area | 20°: 10 mm x 10 mm 60°: 9 mm x 15 mm 85°: 5 mm x 38 mm |
Measurement Repeatability | 0 – 100 GU: 0.2 GU 100 – 2000 GU: 0.2 % |
Measurement Reproducibility | 0 – 100 GU: 0.5 GU 100 – 2000 GU: 0.5 % |
Operating Temperature | 60°F to 104°F |
Relative humidity | Up to 85% non-condensing |
ASTM Standards
ASTM | Title | Link |
D523 | Standard Test Method for Specular Gloss | Link |
D2457 | Standard Test Method for Specular Gloss of Plastic Films and Solid Plastics | Link |
ISO Standards