A Study of Alcohol and Gum Arabic Compatibility.

To determine the influence of isopropanol on fountain solutions, the compatibility of nine commercial fountain etches with alcohol were examined. The compositions of the etches were unknown, but only two were miscible with isopropanol in all proportions. Solutions of arabic acid and of gum arabic at various ionic strengths and pH levels were evaluated for compatibility with isopropanol. At high ionic strength, 50 x 10-3, the compatibility increased with pH to a maximum and then decreased. The compatibility is greater at low ionic strength than at high ionic strength. Arabic acid solutions are more compatible than gum arabic solutions.