Industrialisation and Obsolescence
Hand composition remained the norm for four centuries. Industrialisation then attacked each stage in turn. The iron hand press replaced wood. Steam-powered cylinder presses, introduced at The Times in 1814, raised throughput by an order of magnitude. Stereotyping allowed a forme to be duplicated so several presses could run the same page, and rotary presses printing from curved plates onto continuous paper webs made the mass-circulation newspaper possible.
Composition itself was mechanised late. Ottmar Mergenthaler's Linotype machine of 1886 cast a whole justified line of type on demand from brass matrices, and the Monotype system cast individual sorts from a keyboard. Both replaced the compositor's hand-picking of letters with a keyboard operation, and both remained in heavy newspaper use into the 1970s.
Metal type was displaced not by a better version of itself but by a different principle. Phototypesetting exposed characters onto film, and digital typesetting with laser imaging removed the physical character entirely. Movable type survives today as a craft practice and as a vocabulary: leading, from the strips of lead used to space lines, and uppercase and lowercase, from where a compositor kept the sorts.