Underbase

When you print a colored ink on a dark shirt, the dark fabric shows through and the color looks dull. The fix is to first print a layer of white ink, then flash-cure it, then print the colors on top. That white layer is the underbase.

In screen printing, the underbase adds an extra screen to the job — and an extra trip through the press for every shirt — so it raises both setup costs and per-piece time. But it is the difference between a print that looks vibrant and one that looks muddy.

In DTG, the printer applies the underbase automatically when printing on dark garments. In DTF, the underbase is built into the white-ink layer that backs every transfer. The principle is the same regardless of method.