Build Halftones for White Ink

When printing on dark garments with DTF, you need a white ink underbase beneath the color layer. Halftone patterns control how that white ink is applied — affecting ink usage, feel (hand), and print quality.

When you need halftones

• Printing on dark garments (black, navy, red, etc.)
• You want to reduce white ink usage (lighter hand, less stiff)
• You want softer prints that breathe better
• The design has gradients or photographs that need smooth tonal transitions

Step 1: Open the Halftone Generator

In PrepOS, upload or select your artwork, then click Halftone Generator.

Step 2: Choose your dot shape

Start with Round if you're not sure. It works for almost everything.

Step 3: Set your LPI (Lines Per Inch)

LPI controls dot density:

• 35–45 LPI — large dots, less ink, softer hand, more visible pattern
• 45–55 LPI — medium dots, good balance (most shops land here)
• 55–65 LPI — small dots, more ink, smoother look, stiffer hand

Start with 45 LPI and adjust based on how the final print feels.

Step 4: Set the angle

Dot angle prevents moiré patterns (unwanted visual interference):

• 45° — standard for single-color halftones
• 22.5° — alternative if you see moiré with 45°

Most shops use 45° and never change it.

Step 5: Set min/max dot size

• Min dot size — smallest dot the printer can reproduce (usually 5–10%)
• Max dot size — largest dot before it's solid (usually 90–95%)

This prevents:

• Dots too small for your printer to lay down (results in gaps)
• Dots so large they merge into solid coverage (defeats the purpose)

Step 6: Preview and apply

Click Preview to see the halftone pattern overlaid on your artwork. Check:

• Are the transitions smooth?
• Can you see the dot pattern at print size? (If it's too obvious, increase LPI)
• Is coverage adequate in the dark areas?

When it looks good, click Apply. The halftone layer saves with your artwork.

Step 7: Use in production

The halftoned artwork flows through the normal pipeline:

• Place in MockOS for mockups (the mockup shows the design, not the halftone layer)
• Arrange in GangOS for gang sheets (the halftone is embedded in the print file)
• Your RIP reads the halftone white channel and prints accordingly

Quick reference settings

Tips

• Test on scrap — before committing to a customer order, print a test strip with your settings on the same garment color
• Dark vs. medium garments — dark garments need more white coverage (higher LPI or larger dots). Medium garments (gray, heather) can use less.
• RIP settings matter too — make sure your RIP isn't applying its own halftone on top of yours. Use "pass-through" mode for the white channel if available.
• Save presets — once you find settings that work for your printer + garment combo, save them. You'll reuse them constantly.