Scumming (localized greasing)
High severitySymptoms
Ink marks in non-image areas, localized and persistent
Probable causes
- Worn or badly processed plate
- too little water
- ink rollers marking
- high pH
The Print Guy · 2026-10-05
Other problems in this category
Offset – Ink/Water · TPG-030
Ink over-emulsification
Washed-out colors, short ink that won't transfer, watery haze
Offset – Ink/Water · TPG-031
Tinting (ink in non-image areas)
Slight uniform tint across the whole sheet
Offset – Ink/Water · TPG-033
Excessive dot gain
Dark print, plugged shadows, lost detail
Offset – Ink/Water · TPG-034
Color variation during the run
Sheet 5,000 doesn't match the approved start-up sheet
Offset – Ink/Water · TPG-035
Slow drying
The pile won't dry; can't back up or finish
Offset – Ink/Water · TPG-036
Set-off in the pile
Ink marks the back of the next sheet