| Possible Causes | Solutions |
| Excessive coating of water-based varnish | Decrease distribution |
| High viscosity of varnish | Decrease viscosity |
| Rough surface of the oil coating roll | Repair or change it |
| Water-based varnish dries too quickly | Add slow dry additive |
| Local excessive varnish coating | Adjust the gap |
| Poor softness of varnish | Decrease distribution |
