How does ink trapping and overprinting work in pre-press packaging artwork?

🛡️ Fact-Checked: Packaging Technical Team 📅 Published: 19 Aug 2026 ⏱️ Read Time: ~2 mins 👁 Views: 3

⚡ Direct Answer & Key Takeaways

Understand pre-press ink trapping (spreads, chokes) and overprinting to eliminate unsightly white registration gaps on custom box printing.

Comprehensive Guide & Technical Breakdown

How does ink trapping and overprinting work in pre-press packaging artwork? - Custom Packaging Product Showcase — 📦 Product Showcase: How does ink trapping and overprinting work in pre-press packaging artwork?

On high-speed printing presses, microscopic paper shifts can cause adjacent colors to misalign slightly. Pre-press trapping prevents unsightly white gaps from appearing between touching colors:

### 1. How Trapping Works:

Spread Trap: Expands the lighter background color by a fraction of a millimeter (typically $0.05\text{mm}–0.1\text{mm}$) underneath the darker adjacent color.

Choke Trap: Shrinks the background white cavity so the foreground color overlaps cleanly.

### 2. Overprinting vs Knockout:

Knockout: By default, software cuts out the background color beneath text so inks do not mix.

Overprint (Black Text Rule): 100% Black (K) text should always be set to Overprint. This prints black ink directly over the background color, ensuring crisp, razor-sharp typography with zero risk of white registration borders.