overrun

In printing, overrun occurs when text, spacing, or elements from one line, column, or page flow into the adjacent space beyond the intended boundary. This happens most often during composition, page makeup, or final imposition when type, rules, or image matter does not fit neatly into the allocated area and must be carried forward (pushed to the next line or page) or backward (pulled from the following space) to accommodate it.

Overrun is a practical problem in hand composition and in digital layout work alike. A compositor setting metal type in a justified line might find that the last word cannot fit without excessive spacing; that word then overruns to the next line. In modern pagination software, widows, orphans, and column balancing can force text to overrun across page breaks. The decision to allow an overrun is often made deliberately, as the alternative may be worse: hyphenation, loose spacing, or forced reflow that damages readability.

Sources and management

Overrun stems from several causes: copy that is longer than estimated, font size or measure changes, insertion of new matter, or grid and margin constraints that shift during production. In letterpress and offset, an overrun might mean reprinting a page or signature; in digital workflows, it is caught and corrected before output. Proofreaders and makeup artists monitor for overruns to ensure consistency across signatures and to avoid costly reruns.

The term also appears in binding and finishing: an overrun of edge sheets or spoilage stock beyond the ordered quantity, kept as allowance for waste. In this context it is planned and costed into the job, not an error. Both senses reflect the practical tension between desired layout and the materials and constraints of the press.