solid

In letterpress and hot-metal composition, solid describes text set with no leads (thin strips of lead alloy) inserted between lines of type. The lines of metal type sit directly against one another, producing compact, dense blocks of text on the printed page. This contrasts with open composition, where leads create visible gaps between lines to improve readability.

Solid setting was economical: it consumed less metal, required fewer handling operations, and reduced the physical depth of the composed form. Newspapers and job printers used solid composition for classified advertisements, price lists, and other text where space was at a premium. Casting machines like the Linotype could produce solid slugs without additional lead insertion. However, the result was visually cramped and harder to read, so body text in books and quality publications almost always employed leads of 1 to 3 points between lines.

Solid type can cause technical problems during printing. Metal type expands and contracts slightly with temperature changes; without leads as buffers, lines can lock up or become jammed in the chase during imposition. Ink also transfers less evenly across a solid block because the type cools unevenly during casting, creating micro-variations in height. Printers compensated by using roller composition or careful make-ready, but these added cost and skill requirements.

The term persists in digital typography, where leading (pronounced as in the metal) remains a fundamental parameter. Modern designers inherit the language of the composing room, even though no lead now separates the lines. Solid continues to mean zero leading in font metrics and typesetting software, making it a bridge between the metal era and screen-based work.