The degree to which a paper will allow a reduction in thickness when exposed to a compressing force, as during printing, writing or typing. (The degree to which a paper will resist a reduction in thickness is called its hardness.) A high degree of softness (also known as 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. The degree of softness required varies according to the printing process to be used, and other paper properties involved (in particular resiliency and compressibility which, with hardness and softness, 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. (See also Resiliency, Compressibility, and Hardness.)
The term softness also refers to the degree to which an offset press blanket will reduce in thickness during printing. See Blanket.