Gloss level can be characterized by the angular distribution of light scattered from a surface, measured with a glossmeter, but there are various ways of measuring this, and different industries have different standards.
12.
Jones glossmeter used a geometric configuration of 45?/ 0?/ 45?whereby the surface was illuminated at 45?and two incident reflective angles measured and compared at 0?( diffuse reflectance ) and 45?( diffuse plus specular reflectance ).
13.
A typical glossmeter consists of a fixed mechanical assembly comprising a standardised light source that projects a parallel beam of light onto the test surface to be measured and a filtered detector located to receive the rays reflected from the surface, Figure 1.
14.
For his research he used a glossmeter with a specular angle of 45?as did most of the first photoelectric methods of that type, later studies however by Hunter and Judd in 1939, on a larger number of painted samples, concluded that the 60 degree geometry was the best angle to use so as to provide the closest correlation to a visual observation.
