Gardner Gloss - ASTM D523
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.
Gardner Gloss Measurement
|20°||Good for comparing specimens having 60° gloss values higher than 70.||Equivalent to ASTM D2457 at 20°.|
|60°||Comparing specimens and determining when 20° gloss is more applicable.||Equivalent to ASTM D2457 at 60°.|
|85°||Good for comparing specimens for sheen. Most often used when specimens have 60° gloss values lower than 10.||Commonly known as "Sheen".|