Trapping

Trapping in printing and packaging is a method used to make sure that when different colors are printed next to each other, they overlap just a little bit. This helps prevent tiny gaps between the colors, which can happen because of small mistakes in the printing process. This includes the paper moving slightly or the printing machine not being perfectly aligned. 

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The goal is to make sure the design looks clean and there are no white lines or spaces where the colors should meet.

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Why is Trapping Necessary

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• Paper Movement: Paper can stretch or shift slightly during printing.
• Press Variability: Different printing presses have slight misalignments.
• Ink Spread: Some inks spread more than others, leading to inconsistencies.
• Substrate Properties: Different materials (e.g., paper, plastic, foil) react differently to ink.

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How Trapping Works

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• A lighter color slightly expands (spreads) under a darker color to prevent gaps.
• The overlapping area is carefully adjusted to avoid color shifts or excess darkening.
• Software like Adobe InDesign, Esko, and Kodak Prinergy automate trapping adjustments.

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Types of Trapping

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• Spread: The lighter color is expanded into the darker color.
• Choke: The darker color slightly overlaps the lighter color.
• Centerline Trapping: Both colors expand equally toward each other.

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Applications in Packaging:

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• Common in flexographic, offset, and gravure printing.
• Essential for labels, cartons, and flexible packaging where colors must be perfectly aligned.
• Helps maintain brand consistency and readability of packaging designs.

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