A very simple form of printing was practiced in China and Korea around 175AD. Reverse images in wood, and later bronze were made. These were inked, then paper was placed over the image and gently rubbed with a bamboo stick.
The big breakthrough came around 1440 by Johann Guttenberg of Mainz, Germany. Guttenberg devised a method of casting separate type pieces in an alloy of mainly lead. These could be hand set into pages of text for printing. This method of setting type was to last for around 500 years!
His next task was to invent a printing press. Guttenberg got his idea from observing a wooden wine press. This method of printing is called “Letterpress”. The typeface was inked, the paper was then put over the type and the handle of the press pulled to make the impression.
There were no major improvements until around 1800 when Earl Stanhope made the first iron press. The method of printing was the same as the earlier wooden presses, but a larger sheet could be printed due to the rigidity of the iron.
Various iron presses were made, probably the most well known being the Columbian invented by George Clymer. Clymer took out a patent on his press lasting fourteen years. After this time various manufacturers made similar presses. All of these printing presses were hand inked and therefore relatively slow.
Things speeded up with the next generation of presses – the “platen”.
Earlier platens were treadled and hand fed, but achieved a much greater speed than the earlier hand presses. One reason for this was the rollers which automatically applied the ink. Later platens such as the Thompson Auto and the more famous Heidelberg had auto feeders and drive motors. The Heidelberg achieving a top speed of 5,500 impressions per hour.
Nowadays the design and typesetting is all originated on computers but most printing is done Offset Litho from single sheet fed presses, printing from one to ten colours, or Web Offset colour presses (reel fed). Digital printing is also a growing market for colour printing for smaller runs.
Hot Metal press still retains a small letterpress department for the occasional work needing a visible impression.