Standard techniques for the measurement of paper gloss are capable of providing highly repeatable indices of the gloss phenomenon. However, it is well known that the gloss phenomenon involves more than can be represented by a single number. A recently developed instrument called a microgoniophotometer has been applied to the characterization of paper gloss. The Bi-directional Reflectance Distribution Function (BRDF) plots generated by this device were shown to be related quantitatively and directly to Fresnel's law of specular reflection and to the surface roughness of the sample. Unlike standard gloss meter measurements, the BRDF enables the analyst to distinguish between effects of surface roughness and the Fresnel reflectance factor. Moreover, the analysis provides a way to characterize quantitatively the importance of sub-surface specular reflections to the overall gloss of a coated paper.
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Journal of Pulp & Paper Science 32N1 (2006) 19-23
RIT – Main Campus