platemargin

Platemargin is a term used in printing and plate-making to describe the outer portion of a printing plate that lies outside the intended image area. This non-inked border is established during plate preparation and remains as the plate is mounted on the press. The platemargin serves several practical purposes: it provides clearance for plate registration and mounting tolerances, accommodates minor mechanical drift during a print run, and creates a safe edge that helps prevent ink from reaching the final sheet in case of slight misalignment. It also aids in trimming and die-cutting operations later in the production workflow.

In practice, designers and engineers manage platemargin by placing essential content well within the safe area, while using bleed and crop marks to indicate trim lines. The platemargin itself is typically not printed and is not part of the final image area. The exact size of the platemargin varies with the press, substrate, and format; larger formats or high-precision work may require larger margins to ensure consistent edge quality and registration.

Relation to other concepts: the platemargin is related to, but distinct from, bleed (ink extending to the edge beyond the trim line) and the crop or trim area. The term is most common in plate-making and pressroom contexts; usage can vary by industry and vendor. Outside of printing, the concept of an edge margin on a plate exists in other plate-based processes, but platemargin as a standardized term is not widely used beyond printing workflows.