Gloss has been defined as the attribute of a surfaces that causes it to have a shiny or lustrous, metallic appearance.
The gloss of a surface can be greatly influenced by a number of factors, for example the smoothness achieved during polishing, the amount and type of coating applied or the quality of the substrate. Manufacturers design their products to have maximum appeal. Such examples are; highly reflective car body panels
, glossy magazine covers or satin black designer
furniture. Now what happens when products all of a sudden look different? Customers see this as a defect, or poor quality. Using a glossmeter and having good quality control practices eliminates this variable as a problem.
It is important therefore that gloss levels be consistent on every product or across different batches of products. Gloss can also be a measure of the quality of a surface, for instance a drop in the gloss of a coated surface may indicate problems with its cure- leading to other failures such as poor adhesion or lack of protection for the coated surface.
Gloss measurements depend on the gloss level. Gloss meters are either specific for the paint or multilevel ones.
If Semi Gloss - 10 to 70 GU Measurement Angle: 60 °
If High Gloss > 70 GU Measurement Angle: 20 °
If Low Gloss < 10 GU Measurement Angle: 85 °
The gloss value is determined by directing a light, which has a similar wavelength to the human eye, at the test surface and measuring the amount of specular reflection. Gloss is measured with angles of 60° and 20°. The 60° angle is universal for all applications. The 20° angle gives improved differentiation of measurement on high-gloss coatings above 70 gloss units.