Hot metal typesetting (also called hot lead typesetting or simply hot type) is a method of creating a relief printing surface by injecting molten metal alloy into a matrix. This alloy was typically an alloy of lead, tin and a small amount of antimony. The resulting blocks of type, often called slugs, could range in size from a word to an entire page. It was pioneered by the companies Monotype and Linotype in the late 19th century and their typesetting machines dominated the industry for the next century.

Another variant of hot metal typesetting was stereotyping, where an entire page (or more often, a series of pages called a forme) were assembled and a papier-mache matrix was created from this. The ensuing matrix could be curved, so that plates could be used on a rotary press or flat for the slower flat bed presses.

The nature of text printed via the hot-metal method is notably different than that produced by the phototypesetting processes that followed it. As the lead type used to print a page had been directly formed from the type matrix a good fidelity to the original was achieved. Phototypesetting suffered (at least in its early days) from many problems relating to optical distortion and misalignment. These disappointing results were a thorn in the sides of many authors and readers (especially of complex or mathematical texts that had many small sub and superscripts). A desire to recreate the aesthetic qualities of hot-lead spurred Donald Knuth to create one of the first general purpose outline based font computer typesetting program, T_EX.

See also

• typesetting
• printing
• printing press
• Linotype
• Ludlow Typograph
• Monotype
• phototypesetting

Typesetting

Bleisatz