Fountain solution is an essential element in the offset printing process. How it interacts with other key components of the printing process is critical to producing a quality-printed product.

Basic fountain solution is a formulation consisting of the following raw materials.

*Wetting agents

*Desensitizing agents

*Evaporation inhibitors

*Non-piling additives

*Corrosion inhibitors

*Biocides

Wetting agents, typically surfactants, aid in the cleaning of ink from the non-image area of the plate, reducing scumming and toning. A quality surfactant will lower surface tension. This lower surface tension will allow the plate to “wet out” faster, thus allowing the pressmen to print with the least amount of ink and water required to stay clean. Surfactants also help control emulsification.

Ink must absorb water to print. Too much water produces washed-out color and ink spitting. Too little water leads to color variation and slow clean-ups. A quality surfactant controls how quickly and consistently the wetting will occur on press.

 Desensitizing agents, such as gum Arabic, silicates and phosphates, maintain the hydrophilic, or water loving area, of the printing plate. By attaching themselves to the plate, these agents attract water and at the same time repel ink. Desensitizing agents force the ink to the image area, reducing scumming and toning.

Wetting and desensitizing agents affect the spreading and flow of water across the surface of the plate. Wetting agents make the water spread faster and further while desensitizing agents make the water spread slower and slighter.

Oxidation protection

Evaporation inhibitors are added to help leave a residual amount of fountain solution on the plate during shutdown. The residual fountain solution protects the plate from oxidation and ensures quick clean restarts.

Non-piling additives are designed to lubricate the blanket and soften paper fibers. This aids in lowering paper fiber adhesion to the blanket, improving print quality. Eliminating paper piling is impossible - non-piling additives have been proven to reduce it.

Corrosion inhibitors prevent oxidation and corrosion of the press. They also prevent oxidation and corrosion of the plate during shutdowns. Corrosion inhibitors help ensure cleaner restarts and longer press part life.

Finally, biocides help control bacteria growth. Bacteria are everywhere. Fountain solutions contain many ingredients that will act as a food source for bacteria, including water, paper, gum Arabic and phosphates. Bacteria in your dampening system can cause drastic changes in conductivity and pH, making fountain solution less effective. Bacteria can also clog spray bars and return lines. Simply put, the more bacteria that appear in the dampening system, the more water-related problems you will face on the press. Even though fountain solutions contain several specific biocides to control bacterial growth, they cannot contain enough biocides to totally eliminate the problem.

Communicate changes

As technological advances are made in the printing process (i.e. equipment, inks, paper and plates), new raw materials are found or created. It is important to communicate changes in your printing process with all of your suppliers, and explain your goals and your concerns. In other words, help them help you print a quality product.

It’s easy to adjust your fountain solution and in many cases, a simple change translates into a big improvement in print quality.