Weight-based Ink Trapping Assessment

The motivation to study weight-based ink trapping is to predict overprint colors in wet-on-wet printing. The Preucil formula and other density-derived ink trapping formulas require optical measurement of printed samples, including the measurement of the overprint, in order to compute ink trapping. Yet, ink trapping is obtainable by gravimetric or weight-based method without printing. By means of experimentation, we learned that ink trapping is proportional to the tack difference between the first-down ink (high) and the second-down ink (low). The average gravimetric ink trapping of uni-tack inks in wet-on-wet printing is 0.7 +/- 0.1. This research provides us with insights as we use the ink trapping values as a constant to predict the color of the overprint solid.