Hand typecasting equipment.
© Science Museum / Science & Society Picture Library
Movable type using baked clay was invented in China between 1041 and 1048. In about 1440, Johannes Gutenberg (1397-1468), a German goldsmith, perfected a cheap method of mas-producing movable metal type. It was this, rather than the invention of printing, which aided the information explosion of the Renaisance. The technology remained in use for another 400 years. A copper matrix carrying an impresion of the required character is locked into the base of an adjustable mould and molten metal is poured in. After cooling and trimming, this becomes a piece of type. A skilled worker can produce several types a minute.