Print Laser Pro

DTF Halftones and White Underbase: Artwork Prep Guide

Short answer: For a clean DTF transfer, start with transparent artwork at the intended print size, inspect the halftone dots at that size, and check the white underbase before printing. Print Laser Pro offers a halftone LPI control on selected apparel artwork and separate production export settings for white ink and edge contraction.

Step-by-step

  1. Set the final print size and inspect the artwork

    Choose the intended width and height before judging the dots. Divide image pixels by print inches to find effective PPI: a 900-pixel-wide image printed at 3 inches is 300 PPI. Enlarging a small file does not restore missing detail. Check the transparent background and remove stray pixels around the design.

    • Check both light and dark backgrounds so faint edge pixels are visible.

  2. Preview the halftone on the selected image

    In Print Laser Pro's apparel artwork controls, select the image, turn on Halftone, and adjust Halftone LPI from 15 to 65. LPI controls dot spacing; the right setting depends on artwork, print size, film, ink, and press conditions. Inspect fine lines, faces, and gradients at the final size rather than choosing a number by default.

    • The apparel control applies to the selected image, not every design on a gang sheet.

  3. Check transparency and white ink coverage

    Look for unwanted background color and soft, partly transparent edges. In the production export dialog, select the white ink files your workflow needs. W2 Alpha Threshold controls which pixels receive white underbase; W1 Luminance Threshold is available when W1 is enabled. Inspect the result because white coverage can change how small halftone dots print on dark fabric.

  4. Use edge contraction only where it helps

    The export dialog has an Edge Contraction control from 0 to 5 pixels that pulls spot channels inward. Start at zero, then test a small adjustment if a white fringe appears around the printed color. Too much contraction can leave colored edges unsupported.

  5. Export, inspect, and run a small print test

    Export the chosen print and white ink files, confirm their dimensions and alignment, and preview them in the RIP used by your shop. RIPs differ in how they interpret alpha, white ink, and spot channels, so confirm the channel mapping and ink order there. Print and press a small sample before running a full gang sheet.

Frequently asked questions

What is the difference between PPI and halftone LPI?
PPI describes the image pixels available at the final physical size. LPI describes the frequency of halftone dots. Increasing LPI cannot recover detail missing from a low-resolution image.
Why is there a white halo around my DTF print?
A halo can come from stray edge pixels, a soft alpha edge, white ink extending beyond the color, or RIP settings. Inspect the transparent artwork and white preview first, then test a small Edge Contraction adjustment if the white channel extends past the color.
Does a PNG automatically include a separate white spot channel?
No. A transparent PNG carries color and alpha, but a RIP may generate white ink using its own settings. If your production workflow needs separate white files or spot channels, choose and verify those outputs in the export dialog and your RIP.