Tack stickiness is a critical property of the ink used in lithography. Because the ink sits on a flat surface, it needs internal cohesion; in other words, it needs to stick to itself so that it doesn’t run all over the plate.
However, too much tack can cause it to pull the paper apart. When printing two or more ink colors in line, the ink tack and sequence must be adjusted in order for the ink to adhere to each other as well as to the paper. See also dry trap, lithography, plate, wet trap.