flong

A flong is a flexible papier-mâché mould made by pressing dampened paper pulp against a composed metal type form, then allowing it to dry. It captures the raised surface of the type in precise negative relief, creating a matrix that can be curved or kept flat. The dried flong is tough enough to withstand repeated use yet pliable enough to be shaped without cracking, which made it the standard intermediate step between hot metal typesetting and the casting of stereotype or electrotype plates.

In the stereotyping process, the flong served a critical practical function. A newspaper or book printer working from composed movable type needed to preserve the original layout while producing multiple metal plates for different presses or pages. Rather than risk damage to the original type form, or cast directly into heavy metal moulds that were difficult to position accurately, the printer would make a flong first. This single mould could then be used repeatedly to cast as many stereotype plates as needed, keeping the original type safe for redistribution and reuse.

The standard flong stock was made from two or three layers of paper: a thin facing sheet that captured fine type detail, backed by thicker kraft or newsprint layers that provided structure and resilience. The facing paper was often treated to improve detail capture and reduce drying time. A good flong dried to roughly one-quarter inch thickness and could flex enough to be wrapped around a curved stereotype casting flask, yet remain rigid enough to hold its shape during the hot metal casting process.

Where flongs went wrong

Flongs were labour-intensive to produce and required careful drying conditions, humidity control, and storage to prevent warping or brittleness. A flong left too long before use would become hard and fragile; one exposed to damp would swell and lose dimensional accuracy. The paper could also absorb metal oxides or rust particles during casting, which corrupted the moulds over time. Despite these limitations, flongs remained standard in newspaper production and book work through much of the twentieth century because the alternative, casting directly from type or maintaining separate metal matrices for each page, was more costly and time-consuming.

The term flong derives from the French flan, meaning a blank or flat sheet, and entered English printing vocabulary in the nineteenth century as papier-mâché moulds became the industry standard. By the 1950s and 1960s, as offset lithography and photomechanical methods gradually displaced hot metal composition, the flong became a declining technology. It survives today mainly in industrial contexts where stereotype casting continues for specialist applications, and as a historical reference point in any discussion of mechanical printing production.