Why measure pH and conductivity?
The composition of fountain solution used to be quite simple. Most simply contained acid, alcohol and gum arabic. Control was easy. Press operators mixed a given amount of each and ran the press without trouble. Times have changed! Modern solutions contain all sorts of high-tech additives such as wetting agents, alcohol-replacements and buffering compounds to address environmental and cost concerns. The increasing use of alkaline papers causes more trouble because the calcium carbonate in the paper neutralizes the acid and builds up on rollers and blankets. Failure to accurately monitor fountain solution can cause a host of problems, including scumming, tinting/toning, slow drying of ink, chalking, roller stripping, setoff and premature wearing of plates, to name a few. What is pH all about? pH is used to indicate and control the acidity. Readings above 7.0 are “alkaline”, 7.0 is “neutral”, and readings below 7.0 are “acid”. A reading of about 3.5 to 5.0 is common, but check with the m
