PH + Conductivity = Compatibility As we look at the road to compatibility we must first look at the PH of fountain solution. PH as seen through the eyes of the press operator is a variable that can be controlled. There are many ways to explain PH in the scientific community, but to a printer or press operator it is defined simply by performance alone. If the plate rolls up clean and crisp then we are in an expectable range, if the plate rolls up with a tint toning effect then we are not in an expectable range. What does this all mean? There are three visible observations to take into consideration when using PH to determine performance. Does the plate and ink roll up right away and achieve a balance, and then after a few impressions start to loose balance one way or the other and you end up chasing it all the way through the job (to light or to dark)? Does the plate roll up but then changes to a tint or toning and will not run clean? Does the plate roll up and achieve a balance and holds that balance all the way through the press run? Remember that too low of a fountain solution PH equals Clean and crisp roll up of Plate Minimum picture framing on blanket Emulsification of ink is increased Very slow drying of ink on paper To high of a fountain solution PH equals Slow roll up of plate with ink Toning or tinting in background Drying of ink is acceptable Emulsification of ink is decreased Printed sheet is not clean and crisp Some basic chemistry: 2H2O = (H3O+) + (OH-) goes or is equal to a percentage of Hydrogen ions present, recognized by the PH scale! The percentage of Hydrogen ions present is very important, because this basis chemical reaction with the etch and water will determine what PH we will achieve when mixing fountain solution. It is very important to know the PH and its variation in tap water because the chemical composition of tap water includes trace minerals such as calcium, magnesium and iron, as well as varying levels of chlorination and fluoridation. These contaminating components are all determining factors in how well the fountain solution desensitizes non-image areas, and keep plates and blankets clean and how well the ink transfers from plate to blanket to substrate. Tap water can be subject to variations and fluctuations depending on the season, weather and water treatment, as well as one geographical location to another. Your local city utilities department water quality report is available annually. So when mixing the fountain solution we need to keep in mind the tap water variable and remember to mix with care by always adding acid to a base or etch to the the water to keep Carbonic acid build up to a minimum, also the temperature of the water should be at the recommended 70 to 75 degrees Fahrenheit to promote chemical bonding of etch to H2O. This practice will help ensure the desired performance on press when printing. When the PH of the fountain solution is in the proper recommended rang of 4.50 to 5.50 and the use of SpeedyDry ink additive dryer is used the results are greatly enhanced printed product and service for your customers.