What is drip-off varnish?

It exploits a chemical incompatibility deliberately. The matte primer is laid down from a plate wherever a matte effect is wanted. A gloss varnish is then flooded over the whole sheet. Where the primer is present the gloss will not sit, so it retreats — "drips off" — leaving those areas matte while everything else stays glossy.

The commercial appeal is that this happens inline, in one pass through the press, rather than as a separate finishing operation on a separate machine. That makes it meaningfully cheaper than spot UV for a broadly similar contrast effect, and it removes a step from the lead time.

It is not identical to spot UV, and it is worth being clear about the difference. Spot UV gives a sharper, higher-gloss, more precisely defined edge and can be built up to a raised texture. Drip-off gives a softer transition and a subtler contrast — often more appropriate on a large textured background than on a small logo, and noticeably organic in appearance.

It is also the finish almost nobody in this market publishes, which makes it a useful thing to ask a printer about: it says something about the press configuration and the range of work they actually do.