The degree to which a paper will reduce in thickness when exposed to a compressing force, as during printing. A high degree of compressibility aids in producing a good printed image, as the squeezing down of surface contours enables the printing plate or blanket to contact the paper more completely. Compressibility is a function of the paper's apparent density, the degree of refining the fibers have received during papermaking, and the degree of calendering and supercalendering. A paper's compressibility is also increased by increased moisture content. The degree of compressibility required varies according to the printing process to be used, and other paper properties involved (in particular resiliency and hardness or softness which, with compressibility, define the paper's printing cushion). Generally, easily-compressible paper is preferred for printing, although it is less of an issue in offset printing, and stronger paper may be required in the case of end uses involving folding or handling. A TMI Monitor/printing Surf System can be used to quantitatively measure the compressibility of a paper. (See also Resiliency, Hardness, and Softness.)
The term compressibility also refers to the extent to which an offset press blanket will reduce in thickness under the pressures generated during printing. See Blanket.