color after blanket contamina original tone When darkening occurs, the darker colors are transferred from the blanket over the printing plate onto the succeeding inking system, where they contaminate the light colors. During wet-on-wet printing, the tackiness of the inks must be coordinated. Nevertheless, it can happen that the darker colors from the first printing units contaminate the lighter colors(mainly yellows) in the latter printing units. remedy Change to a different kind of ink Deposit the lighter colors more in the direction of the sheet-feeder 30 Follow the rule of thumb"screen before surface" for the inking sequence. Raise the dampening solution feed in the lighter colors, or increase the lighter colors.