A Microphotogoniometer (MPG) has been developed reporting physical gloss measurements that correlate well with human psychometric responses. Print gloss measurements are typically performed through integration of specular, un-polarized light within an aperture window at a given incidence angle. The later is often chosen depending on the reflector properties. Although such measurements are robust and well accepted by the industry, they often find poor correlation with visual perception.
This instrument allows for the measurement of polarized specular gloss at different surface angles and constant incidence angle. Reflectance data is summarized in terms of a Bidirectional Reflection Distribution Function (BRDF) and then parameterized into several independent gloss components. These components contain information about both surface and material properties and provide additional degrees of freedom for both understanding gloss and gloss metric development.
A comparison of printed and un-printed inkjet photographic media gloss measurements by the MGP and a traditional gloss instrument is presented. Then, a psychometric analysis is employed to compare both techniques. Material and surface properties and their impact on gloss are also discussed.