A fountain solution is a liquid that serves to keep the areas of the plate that do not have printing graphics clean and ink-free. It works by:
- Wetting the blank part of the printing plate.
- Generating a metal oxide or hydrophilic salt layer.
- Establishing a barrier between the blank part and the ink.
- Desensitizing the non-image areas, rendering them ink-repellent.
- Retard friction wear increasing plate life.
- Prevent the ink train and plate surface from overheating.
A fountain solution is made up of water, a buffer salt that keeps the pH between 4.8 and 5.5, isopropyl alcohol in the proportion of 6% to 8%. Other ingredients in a fountain solution include Lubricants, Release agents for the blanket, Wetting agents, also known as Surfactants, Glycerin, various Glycols.