Also called surface strength, the extent to which a paper can withstand a force applied at right angles to its surface (such as that generated by a sticky ink film during printing) without rupturing, or picking. Picking can include either a delamination of the plys of a paper and/or a partial or total removal of a paper coating. Pick resistance is enhanced by increased internal bond strength, as well as increased fiber refining prior to papermaking, a decreased use of fillers, increased surface sizing, or a more liberal use of binders in coatings. However, pick resistance is increased to the detriment of other properties (see Paper and Papermaking: Paper Properties.) Pick resistance is more of a concern in letterpress and offset printing than in other printing processes. The term wet pick resistance refers to a paper's ability to resist picking after it has been exposed to moisture (in contrast to its dry pick resistance). Moisture can decrease a paper's surface bond strength, making it more susceptible to picking (called wet picking, in contrast to dry picking).
Various tests can determine the pick resistance of a paper. (See Dennison Wax Test and Printability Tester.) The pick resistance for offset papers is best determined, however, in conditions that best simulate printing processes using progressively tackier inks and a pick tester.