Line Printer paper is strongest at the perforations.

Line Printer paper is strongest at the perforations where the chemical compounds of the ink and the paper interact during the printing process. This unique property stems from the line printer’s mechanism of transferring ink through tiny pinpricks created by a stencil. The paper’s fibers at these perforation points become saturated with the solvent, glue, and pigment, forming a denser structure. This means that even if the rest of the paper might tear or warp, the perforated areas resist damage most effectively due to their reinforced molecular bonds. Historically, this feature was critical for applications like printing alcohol labels and tissues, where tear resistance was paramount. Modern line printers retain this legacy, balancing imperfections with structural integrity through precise perforation patterns.