Factors Affecting the pH and Conductance of Alkaline Fountain Solutions.

The chemistry of alkaline fountain solutions is discussed. Changes that occur in the electrical conductivity and pH of alkaline fountain solutions are shown to be the result of water hardness variations of the diluting water and of the interaction between diluted fountain solution with paper and atmospheric carbon dioxide. Oil base inks are shown to have little effect on either conductance or pH. Conductance measurements, which are easily performed, are shown to be superior to pH measurements for fountain solution control purposes.