An undesirable peripheral outline around the edges of the printed image. There are two halo faults:
- Too much impression pressure between the plate and substrate;
- Too much anilox pressure;
- Backing tape too thin or too firm;
- Plate dureometer too hard;
- Plate cylinder running out of round;
- Excessive plate grinding.
- Adjust the pressure between the plate and impression cylinder eliminating halo all around the image;
- Adjust pressure between anilox roll and plate roll to eliminate lead and trailing edge halo;
- Remount plates with cushion mounting tape;
- Use recommended plate durometer;
- Plate cylinder may be out of round; have checked for concentricity. (T.I.R.);
- Reduce amount of plate grinding.