Nine out of ten DTG complaints are pretreat, not printing. The printer is usually doing exactly what it was told. The variable is the chemistry underneath.
1. Dull, grey or thin white
Cause: too little pretreat, or not dried properly.
Fix: increase the applied quantity and confirm by weight. Then press longer or hotter until the panel is genuinely dry and flat. Weighing is the important part; "looks about right" is how this drifts week to week.
2. Visible box or halo around the print
Cause: the pretreated area is bigger than the print, or its edge is hard.
Fix: spray only slightly beyond the print, feather the edge rather than stopping abruptly, and press the whole panel so any sheen change is consistent across it.
3. Patchy white, blotchy coverage
Cause: uneven application, a partially blocked sprayer nozzle, or an uneven press platen.
Fix: clean and test the nozzle onto paper, check the spray pattern, and check platen contact across the whole area. Worn platen foam causes pressure differences that look exactly like a chemistry fault.
4. Print washes off or fades badly after one wash
Cause: under-cure. The ink and pretreat never fully bonded.
Fix: verify actual temperature at the garment with a probe or temperature strip, not the machine's display, and extend the cure. Then wash-test a sample before shipping, as in the QC checklist.
5. Stiff, plasticky hand
Cause: too much pretreat, too much white, or double-curing.
Fix: reduce pretreat to the measured minimum that still gives a clean white, reduce white underbase density in the software, and cure once properly rather than twice partially.
6. Pretreat marks on the garment away from the print
Cause: overspray, drips, or handling with pretreat-contaminated gloves and platens.
Fix: contain the spray area, wipe the platen between garments, and keep pretreated garments away from finished ones. Contaminated platens transfer marks all day before anyone notices.
7. Poor results on a specific garment
Cause: fibre content or a garment finish. Polyester blends, bamboo, viscose and heavily softened or water-repellent finishes all behave differently from combed ring-spun cotton.
Fix: test every new blank before promising it, and keep a list of blanks that work. See choosing blanks.
8. Inconsistent results between mornings and afternoons
Cause: ambient humidity and temperature, and press recovery time.
Fix: let the press reach temperature between garments rather than working faster than it recovers, and note humidity if your results swing seasonally. Shops in humid climates often need longer drying.
The reference table
| Symptom | First suspect | Second suspect |
|---|---|---|
| Dull white | Too little pretreat | Under-dried |
| Visible box | Over-sprayed area | Hard edge, partial pressing |
| Patchy white | Nozzle or spray pattern | Platen contact |
| Washes off | Under-cure | Pretreat and ink mismatch |
| Stiff hand | Too much pretreat | Too much white ink |
| Random marks | Overspray | Contaminated platen |
| One garment only | Fibre content or finish | Untested blank |
| Time-of-day drift | Press recovery | Humidity |
Make it measurable
Every fix above depends on knowing what you did last time. Record applied pretreat weight, press time and temperature, and cure settings against the job, then a reorder can be reproduced rather than re-guessed.
Printer's Friend tracks pretreat per line item and holds the cure schedule on DTG jobs, so the settings live with the order. Pricing the extra pretreat and white ink properly is covered in how to price DTG.