Method and means for indicating the condition of a universal fountain solution for planographic printing

摘要

For monitoring the condition of a universal fountain solution for planographic printing, a concentrated universal fountain solution is premixed with a color-change indicator material of predetermined characteristics such as lichen blue. The concentrated fountain solution is provided at a pH above about 3.5 and below about 4.5; the diluted fountain solution is formed by diluting such concentrated solution with water. The contamination occurring during planographic printing which is detrimental to fountain solution effectiveness and printing quality causes the pH of such diluted solution to increase. The indicator material provided initiates a change in color of the diluted fountain solution at a pH when the solution is beginning to lose effectiveness and provides an intense color change as pH increases to a level indicating that the solution should be changed in order to avoid deterioration in the desired quality of printing.