Paper varnish is a liquid coating applied to printed box surface after the coated paperboard is litho printed.
Varnish was first introduced to the printing industry as they are essentially transparent inks without a pigment. They are applied as the CMYK inks during the printing process. Paper varnishes could give the paper surface a smooth and consistent texture. It also has the added benefit of sealing the printed material to help preserve it better.
How Varnishing Works
Spot UV varnishes are common used UV surface varnishes. It is cured or hardened by UV light during the printing process. Films are commonly used to match the UV position perfectly.
When making paper boxes and bags, UV varnishes are often used for logo as a spot application where only specific parts of the box and bag surface get a UV varnish. For flexibly used UV spots, it can also give effectively texture to different areas on boxes and bags, and leave other area untreated.