Definition
White underbase is the layer of white ink jetted between the color layer and the adhesive on a DTF transfer. It masks the underlying garment color so the design renders at full opacity on any fabric shade including black, navy, and dark heather. The underbase is generated automatically by the RIP software based on the alpha channel of the source artwork.
Why DTF Uses White Underbase
Apparel comes in every color. Without a white underbase, color ink on a colored garment looks muddy or muted because the garment color shows through the translucent ink layer. The white underbase acts as a primer coat, masking the garment color and giving the CMYK color layer a pure white background to print against. The result is full-saturation color regardless of fabric shade.
How Underbase Is Generated
DTF print engines include a dedicated white ink channel alongside CMYK. The RIP software analyzes the source artwork, identifies every non-transparent pixel, and generates a corresponding white channel that prints underneath the color. The white channel is typically choked slightly inside the color boundary so it stays hidden when viewed from the print face. Long Island DTF Printing tunes underbase density per design to balance opacity with hand feel.
When Underbase Is Required
Underbase is required for any garment darker than off-white. Black, navy, royal, athletic gold, charcoal, heather gray, and most heathered colors all need underbase. On pure white garments, the underbase can be reduced or skipped entirely for a softer hand feel. The decision is automatic at the RIP stage based on the destination garment specified at order time.
Underbase Visibility Issues
On a well-tuned DTF transfer, the white underbase is hidden beneath the color layer and never visible. Poorly tuned RIP software can produce visible white halos around the design edges when the underbase is not choked properly. Long Island DTF Printing's production pipeline includes per-design choke tuning to eliminate underbase halos before transfers ship.
Cost Impact
Underbase is included in the $0.06 per square inch flat rate. Unlike screen print where white underbase is a separate spot color requiring its own screen and setup fee, DTF underbase is generated digitally with no additional charge. This is one of the structural cost advantages of DTF over screen print transfers for full-color and dark-garment work.
Related Reference
- What Are DTF Transfers — Construction reference.
- How DTF Works — Full production chain.
- Glossary: White Underbase — Term definition.