Johannes Gutenberg wasn’t the first to think of movable type. All the way back in the 11th century, a Chinese inventor named Bi Sheng came up with the technique. But he utilized porcelain, which is a hard, glass-like material. Mr. Gutenberg made a version of movable type that was much easier to use. 

For printers in Mr. Gutenberg’s day, the recipe for making letters might have looked something like this:

Step 1: Carve a letter onto the end of a piece of steel. 

Step 2: Use a hammer or mallet to punch the steel into a softened piece of copper. Let the imprint of the letter cool (about 30 minutes). Once it cools, the shape of letter in the copper is ready to go into a mold. 

Photo: Hand mold (Gutenberg Museum/D. Bachert)

Step 3: With the letter inside, pour very hot metal into the mold. Lead-tin alloy is recommended. 

Step 4: The liquid metal will cool fast. The letter should be ready in less than five minutes. 

Photo: Type case at the Gutenberg Museum printing workshop (Gutenberg Museum/Carsten Costard)

Mr. Gutenberg’s design really sped things along. A printer could make around 4,000 letters every day with the mold Mr. Gutenberg made. That came in handy since there were about four million letters in the first Gutenberg Bible. 

The printers put each letter into a hollow slab of wood. That’s called a reading stick (or composing stick). It helped the printer keep the letters in order. The printer then took each letter and placed it onto a long slab called the press bed. The press bed got covered in ink and a piece of paper was placed on top. 

Photo: The Gutenberg Museum Workshop (Gutenberg Museum/Carsten Costard)