The factors which are responsible for the surface reflection of coated paper at specular angles have been explored by means of models of specular reflection and of coating roughness. The model of specular reflection used is based upon the addition of the roughnesses which arise from independent sources, i.e. the roughness caused by the base paper on the one hand, and by the coating pigments on the other. Coating surface roughness is approached theoretically by the incorporation in a model of the influences of particle shape and size, size distribution and the hypothetical statistics of particle position at the surface.
The theoretical predictions have been tested with the aid of experimental data, on specular reflection, Hunter gloss, profilometric roughness, and particle size. The samples studied were different types of coated paper, blade-coated on a pilot scale.