Misregistration happens when different colors in a design don’t print in exactly the same position on the page. Printing presses lay down colors one at a time (usually Cyan, Magenta, Yellow, and Black—aka CMYK). If those layers shift even slightly during printing, the colors don’t line up the way they should. Even the most high-end presses can experience tiny shifts during printing. Common causes include paper movement, mechanical issues, or temperature/humidity.
Misregistration can show up as thin white lines between colors, a colored “halo” around text or objects, blurry or dobled edges, or text that looks out of focus. It can be subtle or very noticeable, depending on how far the colors are off. Trapping adds a slight overlap between colors so that if they don’t align perfectly, you don’t get those ugly gaps. The overlap hides the misalignment.