Files & prepress
What is trapping?
Trapping is building tiny overlaps between adjacent colours so that slight registration error shows an overlap instead of an unprinted gap.
Where two colours meet, a hair of misregistration leaves a white sliver; trapping spreads the lighter colour a fraction into the darker so the miss lands on overlap. Screen printers live by it — every screen is a separate registration event.
Single-pass digital printing has no inter-colour registration to miss, so trapping barely matters for most large-format work — until it does: print-and-cut jobs trap against the CUT line (that's what bleed is), and layered cut vinyl needs the same thinking with knives instead of ink.
Related terms
Software that speaks the trade
PrinterFlo runs print & sign shops on one board — quotes that price by size and material, proofs approved from one link, and a production checklist the quote writes for you.