Permeability - What is permeability?
A measure of the extent to which a porous material, such as paper, will allow a gas or liquid to pass through it. The permeability of a material is related to its porosity (the volume of the material that is made up of voids or empty spaces) but is also determined by the shape of and connections (or lack of connections) between the voids in a material.
Permeability can determine how much adhesive or ink will soak into a sheet of paper. A highly permeable paper will have good adhesive or ink receptivity, resulting in a high quality adhesive bond or print respectively. Permeable papers are ideal for high speed printing processes, as when printing newspapers, where the ink needs to be absorbed rapidly to reduce the risk of smudging. However, it can also result in strike-through. Papers with poor permeability can lead to print smudging, poor adhesion, and usually have greater problems with dimensional stability due to issues with moisture content.