The damping process transfers a water-based dampening solution to a printing plate in offset lithographic printing. A dampening solution ensures that the non-image areas become ink-repellant.
The offset lithographic printing process works on the principle of keeping water and oil bases separate. Thus the damping process prevents the oil-based ink from collecting in undesirable areas of the printing plate.
It moistens the non-image areas so that they won’t accept the ink rollers. The water-based solution, also called the fountain solution, consists of alcohol, acid, gum, a corrosion inhibitor, and an anti-foaming agent. However, the amount of water transferred to the printing plate is very critical to obtain good offset printing.