DTF Glossary
Varnish channel
A varnish channel is a separate grayscale production plane that tells a UV-capable workflow where to place clear coating. It is not process colour, transparency, or white underbase. Its coverage, name, polarity, and optional outward spread must be validated against the exact RIP, printer, ink, film, curing, and transfer process.
In practice
Spread grows the varnish mask outward; choke shrinks a white mask inward. Applying the wrong operation can leave an uncovered edge or place coating beyond the intended design.
NestSheet can write varnish spots in selected TIFF and PSD/PSB recipes with V1–V4 naming and a 1 px default spread. Dedicated UV-DTF mode is not yet a shipped user mode.