Dampening cloths are used to apply a dampening solution (water) to the printing plate, which is necessary to prevent the ink from drying out on the plate. The dampening solution helps to transfer the ink from the plate to the blanket and then to the paper. Dampening cloths are typically made of a porous, absorbent material, such as felt, that is designed to pick up and hold the dampening solution. They are mounted on a roller and are in contact with the plate cylinder and fountain roller. As the plate cylinder rotates, the dampening cloths pick up the dampening solution and transfer it to the plate, ensuring that the right amount of water is applied to the plate. This process helps to prevent the ink from drying out on the plate, keeping the ink consistent and preventing smudging and other printing errors. Dampening cloths are typically cleaned after each print run to remove any excess solution, and they are also replaced periodically to ensure consistent application of the dampening solution.