Gloss - ASTM D2457
Gloss is a measure of how shiny, or reflective a material is at a specified angle based on refractive index.
An incandescent light source is directed at the test specimen at a specified incidence angle. A receptor is located at the mirror reflection of the incident beam. Polished black glass with a refractive index of 1.567 is used as a standard and is assigned a gloss of 100 at all geometries. Measurements are made using a glossmeter.
|20°||high-gloss films||Equivalent to ASTM D523 at 20°.|
|45°||intermediate and low gloss films|
|60°||Intermediate-gloss films||Equivalent to ASTM D523 at 60°.|
Comparison of gloss data can only be made between similar materials and test procedures. Gloss values for transparent and opaque materials are not comparable. Gloss varies with smoothness and flatness and is sometimes used to compare these attributes.