Digital paper and print surface topography

Paper is a complex composite material. Its structure and its surface greatly influence its runnability and its printability. The roughness is primordial for the absorption and the spreading of inks. It also plays a major role to determine the amount of coating. The paper surface characterization is crucial for understanding light reflection and scattering that control the level of gloss. The paper Surface topography can be approached with different techniques, Such as air leakage instrument, Stylus technique or optical devices. From this mapping, parameters call be calculated according to a TAPPI standard. However a huge number of parameters exist; the most common is the root mean square of the height distribution of the surface S, This paper investigates the digital paper topography by calculating the smallest surface statistically representative of a given paper grade. Two algorithms are compared. In a second part the surface modification due to laser print is studied for different halftoning coverage. Measurements are compared to a model we developed.