ABSTRACT
The uniformity and structure of paper is highly dependent on the spatial arrangement of its fibers, fines and other components. The surfaces of paper are commonly referred to as the wire side and felt or top side. Traditionally these sides have had very different characteristics, but, with the recent emphasis on quality, particularly print quality, more effort is being expended by the papermaker to minimize these differences. Subsequent converting operations such as calendering (hard nip, soft nip, and supercalendering) are used to improve the surface characteristics of paper while maximizing bulk without adversely effecting mechanical properties. Improvements in surface structure and properties can be achieved by surface coatings applied, for example, by roll, air knife, or blade methods. Failure of the surface or surface layers implies that applied surface stresses are exceeding the surface strength of the paper when the appropriate stress concentration factors are accounted for.
