(Optional)
3.1 : The ratio of the specularly reflected light to the incident light, measured at a specified angle. astm d523 pdf
9.1 No calculations are required; the gloss value is read directly from the instrument. (Optional) 3
8.1 The glossmeter is positioned on the test specimen, ensuring that the light source and receptor are at the specified angles (usually 20°, 60°, or 85°). 8.2 The gloss value is read directly from the glossmeter. astm d523 pdf