Foil jobs fail for a short list of reasons: wrong substrate, ink under the foil area, poor die or registration, or file art that is too fine for the process. Fix these and you avoid most reprints and disappointment.
Adhesion failure
Foil does not stick when the surface rejects it: heavy coating, wet ink, or incompatible stock. Knock out ink where foil will go; use a foilable substrate. Test unfamiliar stocks before the full run.
Registration and coverage
Misregistered foil looks off or overlaps ink. Trap (gap or overlap) must be correct. Fine detail or hairline art may not stamp cleanly; the die or foil cannot hold that resolution. Simplify art or increase minimum stroke where needed.
File and die mismatch
The foil layer must match what the die maker expects. Wrong layer, open paths, or raster art cause wrong dies or rework. Provide a clean vector foil layer and confirm with the printer before the die is made.
Checklist before production
• Substrate approved for foil.
• Knockout and trap correct in the print file.
• Foil layer is vector, closed shapes, and matches printer spec.
Common mistakes
Sending a file with no knockout, or with foil art that is too fine. Both cause rework or a failed run. Confirm file and substrate with the printer before the die is made.