How to add bleed to a PDF
Extend artwork past the trim so a drifting cut never leaves a white edge.
Size the document to trim + bleed
Build the page at the finished size plus bleed on every edge — an 8.5 × 11 in page becomes 8.75 × 11.25 in with 0.125 in bleed. The bleed calculator gives you the exact numbers.
Extend backgrounds to the bleed line
Any color, image, or artwork touching the edge must run all the way to the bleed line, not just the trim. Stopping at the trim is what causes white slivers.
Keep text inside the safe area
Pull text and logos at least 0.125 in inside the trim so the cut never clips them.
Turn on bleed in the export settings
In InDesign, Illustrator, or Affinity, set the bleed in Document Setup and, on PDF export, enable "Use Document Bleed Settings". Add crop marks only if your printer asks.
Verify the box nesting
A correct print PDF has a BleedBox larger than the TrimBox. Preflight checks that MediaBox ⊇ BleedBox ⊇ TrimBox and reports a missing or insufficient bleed with page references.
FAQ
How much bleed does a PDF need?
0.125 in (3 mm) on every edge is the common default; large-format work may want 0.25 in. Your printer’s spec always wins.
Why does my PDF print with a white edge?
The background stops at the trim instead of extending into the bleed, so when the cut drifts by a fraction it exposes the unprinted paper.