Movable metal type
The invention of printing with movable type in Europe in the 1450s revolutionised the production, movement and distribution of books. Printing could produce the familiar look of hand-written books in a fraction of the time, at a significantly reduced cost and in far greater numbers.
Movable type made from baked clay had existed in China since the eleventh century and in Korea metal type was also used in printing. The oldest surviving metal type printing is a Korean Buddhist document published in 1377. However, there is no evidence to suggest that this technology was used on a large scale. In the case of Chinese, because the language consists of so many different characters, it would have been impractical to cast and compose individual pieces of type. Nor is there evidence that this technology reached the West via the trade routes.
Because of the secrecy surrounding Johann Gutenberg's invention, we cannot be entirely sure how he cast the first types. However, we do know how type was cast later in the fifteenth century (and continues to be cast by a few enthusiasts today):
The first step in making a piece of type is to make a punch. This is made from a steel rod, on one end of which the letter-cutter cuts the individual letter in relief (a positive image). The punch is then hammered into a small block of copper, called a matrix (a negative impression). The matrix is then fitted into the bottom of a mould: a steel box made in two parts, clad in wood for insulation and held together with a sprung catch. The type-caster holds the mould in his right hand and pours liquid metal (a mixture of lead, tin and antimony, which hardens quickly) into it with his left, instantly giving the mould an upward jerk to force the metal all the way to the bottom of the matrix. The type-caster releases the spring, the piece of type (called a sort) falls out, and he repeated the process. A good type-caster could produce about 4,000 sorts in a day.
Gutenberg's contribution was to take the idea of impression from inked letterforms and create a practical and efficient way of so doing. The three fundamental features of his discovery were: the casting and production of individual pieces of movable type; the adaptation of existing hand presses to withstand the rigours of printing; and the invention of a sticky oil-based printing ink. With these innovations he produced one of the most beautiful and technically perfect books ever printed - the 42-line Latin Bible of c.1455, now known as The Gutenberg Bible.
Gutenberg is the one who perfected the printing invention to such a degree that it evolved from a non-practical process to an extremely practical one. One of the main advantages of his system of using movable metal type is that after setting and printing a page or sheet, the type can be broken up and the individual sorts redistributed in their cases for printing another page.