Plugging
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. |
