The shadows and tight reverses start to fill in and become “plugged” with ink during the run.

CAUSE CURE
Plate becomes sensitive and accepts ink. Clean plate with a good acidic plate cleaner and re-gum the plate with a gum finisher. Replace plate if it does not clean up.
Improper fountain solution or dosage. Check press mix for proper dosage, pH and conductivity. Adjust concentration to specifications. Consult fountain solution supplier.
Contaminated chemistry. Dump and re-batch chemistry.
Ink becomes water logged and emulsified. Reduce water settings to achieve better ink and water balance. Consult Ink supplier.
Improper pH of fountain solution. Check pH of press mix and adjust accordingly to a pH of around 4.0.
Pressure settings too high. Adjust blanket and plate pressures to specifications. Make sure blanket and plate are packed to specified heights.
Water settings too low. Adjust water settings until problem is eliminated.
Plate not processed properly. Consult plate manufacturer and prepress to ensure plate is being processed correctly.