Transparency and white underbase: why soft edges print as a halo On a dark shirt, every half-clear pixel gets white ink under it.
On dark garments, DTF, DTG and screen printing put a white underbase under the colors so they stay bright. The underbase follows the artwork's shapes: where the file is solid, white goes under it; where it is partly transparent, the RIP or the separator has to decide, and soft edges, glows and drop shadows often end up as a pale halo. Artwork for these processes works best with crisp edges, solid colors and no semi-transparent effects.
What the underbase does
Ink on a dark shirt looks dull because the fabric shows through it. A white layer printed first gives the colors something bright to sit on. In screen printing it is a separate white screen; in DTF and DTG the printer's software builds the white layer from the artwork file.
Where the halo comes from
- Anti-aliased edges: a raster logo's edge pixels are part color, part transparent, so the white layer reaches slightly past the solid color.
- Drop shadows and glows: they fade to transparent, and the white under them shows as a pale cloud.
- Gradients to transparent: the fade has no clean edge for the white to stop at.
- Leftover background pixels: a nearly invisible edge from a removed background still gets white under it.
How each process handles it
| Process | How the white layer is made | What helps the artwork |
|---|---|---|
| Screen printing | A separate white screen, usually choked slightly inside the colors | Solid vector shapes and clean spot-color separations |
| DTF | White printed under every pixel that isn't fully transparent | A high-resolution file with hard edges and no soft effects |
| DTG | The RIP builds the white from the image | Hard edges, true colors and no near-invisible background pixels |
How to set the artwork up
- Use solid colors and hard edges; avoid glows, soft shadows and fades to transparent.
- If the design needs a shadow, draw it as a solid shape in a real color.
- For DTF and DTG, send the artwork at full print size, at the resolution the printer asks for.
- For screen printing, send vector art so the separator can build and choke the underbase.
For the ink-stacking side of this, see overprint vs knockout.
Where a redraw helps
A raster logo with soft edges can't be fixed by turning up contrast: the edge pixels are still part transparent. Redrawing it as vector gives every shape a clean edge, so the underbase and the colors line up. VectorWiz redraws the artwork; preparing the garment print itself stays with your printer.
Get it redrawn as clean vector, set up for the job.
A designer redraws it by hand as closed paths, with the colors and layers your process needs, in 24 hours.
Need something custom? Email hello@vectorwiz.com
Frequently asked questions
Why is there a white outline around my DTF print?
The artwork has soft or semi-transparent edges, and the printer put white ink under them. Crisp edges and solid colors stop the halo.
Do drop shadows work on dark garments?
Soft ones usually print as a pale cloud, because white goes under the fade. A shadow drawn as a solid shape in a real color prints cleanly.
Does screen printing have the same problem?
Less often, because the separator builds the white screen by hand and usually chokes it slightly inside the colors. Soft effects still need to become halftones or solid shapes.
Can you fix my logo for DTF?
We redraw it as clean vector with hard edges and true colors, and deliver files your printer can output at any size. We don't edit photos or remove backgrounds.
Naimur Rahman
Leads design direction and quality at VectorWiz. Reviews and redraws production artwork by hand across sign, screen-print, embroidery, and CNC work.
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