The roughness of a certain surface is often of importance for the user and thus specified. When this is the case there is a good chance that the method used to describe the roughness is a method according to Bekk, Bendtsen, or Sheffield, a PPS method (PPS or PPS-Flex) or the Stylus Roughness method.

All but the last of these methods are air-leak methods which indicate the roughness of a certain paper surface by telling how much air passes between the edge of a measuring head and the surface in question, under specified conditions. The PPS-method has a rather limited measuring range and is mainly used for smooth grades e.g. for printing. The Bendtsen and Sheffield methods are air-leak methods with a relatively wide measuring range. They have over the years been found reliable, simple to use and good all around methods for determination of surface roughness on many grades. The stylus roughness method uses an entirely different approach.