UNDERSTANDING GLOSS ANISOTROPY IN MACHINE-MADE PAPERS

Directional reflectometers measure a reflectance that is dependent on the instrument geometry and polarization, and the topography and orien tation of the paper surface. Each of these factors may contribute to d ifferences in the gloss measured in the MD and CD directions, in which case the gloss is said to be anisotropic. We examined gloss anisotrop y as a function of gloss angle on a variety of paper grades. Gloss ani sotropy was found to be most influenced by the specular component of t he reflected light and, in particular the surface reflectance. A new m odel is presented that attributes gloss anisotropy to the fibre edge d istribution.