Fountain Solution

/ˈfaʊntən səˈluːʃn/

General Definition

Fountain Solution is a critical liquid composed of water and various chemical additives used in the offset lithography process. Its primary purpose is to moisten the non-halftone or non-dot areas on the printing plate to prevent these areas from accepting ink, thus maintaining the essential water-ink balance. This solution is typically a complex mixture of alcohol or alcohol substitutes, surfactants (surface-active agents), and buffers to control pH.

Real-World Usage

Correct use of Fountain Solution is a key factor in the color quality and stability of offset printing. This solution constitutes the core of the offset press's Dampening System. If the solution is improperly regulated (e.g., unsuitable pH or conductivity), it can lead to severe issues like excessive ink-in-water emulsification (resulting in smearing and quality degradation) or poor plate desensitization (causing ink to stick to non-image areas).

Press Supervisors and Specialists continuously measure the solution's pH (typically between 4.5 and 5.5) and conductivity. Precise control allows the press to operate with the minimum amount of water necessary, which in turn increases the ink drying speed and ultimately improves production efficiency and process stability.

Consultant's Note

The primary risk associated with a poorly balanced Fountain Solution is Scumming, where ink contaminates the non-image areas of the plate due to inadequate water repulsion. This failure in the water-ink balance results in undesired marks and dirty backgrounds. Additionally, the excess moisture that inevitably transfers into the ink slows down the drying process. This delay directly increases the risk of severe production problems such as Setoff (ink transferring to the back of the next sheet).

It is essential for printing specialists to test the new solution under real conditions and record new Ink Transfer Curves. This measure ensures that the water-ink balance is maintained at the highest level of stability, preventing the economic losses associated with material and color waste.

Aligned with: ISO 12647-2 (Offset) / G7 / Press Chemistry Standards