Gutenberg’s printing press: lead type, oil-based ink and a wooden press

By the middle of the 15th century, books in Europe were generally copied by hand, and each copy was made separately. Then, in the German city of Mainz, a craftsman combined several older methods into a system that could print hundreds of identical copies of a single book. His name was Johannes Gutenberg. His printing press became a major turning point in the history of the spread of knowledge.

The craftsman of Mainz

According to the Library of Congress in the United States, Gutenberg lived from about 1400 to 1468. His date of birth is not known, and few documents survive about his family. According to the Harry Ransom Center at the University of Texas, he probably began work on printing technology as early as the 1430s. In the mid-1450s he published his first major book in Mainz with his partner Johann Fust.

Printing from wooden blocks had existed before. In Part 39 of this series, we saw that movable type made of clay in China and of metal in Korea had been developed before Gutenberg. The Library of Congress also writes that Gutenberg’s book was the first printed in Western Europe with movable metal type, because this had been done in Korea nearly a century earlier. Gutenberg’s achievement was that he solved the problems of casting type, ink and pressure together.

The hand mould: the heart of the invention

Printing required thousands of small metal letters, and all of them had to be exactly alike. According to Julia Bangert, a researcher with the International Gutenberg Society, the solution was the “hand mould”. She calls it the “heart” of Gutenberg’s invention. It was a hollow metal mould in two parts, with a channel for pouring in molten metal. It was fitted in a wooden frame so that the craftsman could hold it in his hand.

At the bottom of the mould, the letter’s “matrix” was clamped with a metal spring. It could be adjusted to the width of each letter, because letters do not all have the same width. According to Bangert, Gutenberg’s original metal recipe is not known. Later details suggest it was mostly lead, mixed with tin and antimony. The alloy set and cooled in the mould at once, so the letter could be removed straight away. Each letter was then carefully filed to the same height, because a taller letter would press harder on the paper and a shorter one would not print at all.

Oil-based ink

The second problem was ink. Bangert writes that ordinary water-based writing ink did not work on metal type, and the printing came out pale and brown. Gutenberg borrowed the recipe for oil-based colours from painters. He tried mixing turpentine, linseed oil, walnut oil, resin, pitch and lampblack until he produced a deep black ink. The ink was applied with two leather balls stuffed with wool or horse hair and fixed to wooden handles.

From the wine press to the printing press

The third part was the press itself. According to Bangert, Gutenberg made use of the wooden screw presses of his time, such as those used to press grapes or paper. But they had a fault. When the screw turned, the pressing plate turned with it, and the print smeared. Gutenberg fitted a small part between the screw and the plate to stop the plate from rotating. The paper was lightly moistened and pinned in a frame. Another frame was placed over it to keep the edges clean. It was then pressed down on the inked type.

The first major book

According to the Library of Congress, Gutenberg’s famous large Latin book, now called the Gutenberg Bible, appeared around 1455. About 180 copies were printed: 145 on paper and 35 on vellum, a fine writing material made from animal skin. Of these, 49 copies survived into the 20th century, and 21 of them are complete. One complete vellum copy is in the Library of Congress in Washington, and the other two are in Paris and London. Even in the paper copies, headings and decorations were added later by hand.

One machine, centuries of influence

According to the Library of Congress, printing with movable type made texts available to far more people in Europe. It is linked to the Renaissance and the Scientific Revolution. Several discoveries covered in later parts of this series, such as the Copernican system and Napier’s logarithms, appeared in the form of printed books. The newspaper is also a descendant of this invention. When an issue of Roznama Atemad is printed in Quetta today, the same basic idea is at work that a craftsman in Mainz tried about 575 years ago: set the type once, and print as many times as you want.