Stage4

Offset Printing

In 1875, Robert Barclay invented the offset press for printing on metal. Then, in 1904, Ira Washington Rubel adapted the technology for paper. This indirect method of printing is based on a very simple chemical phenomenon: the repulsion between oil and water.

The printing process is anything but simple though. An offset plate is divided into two areas: the image area, which is lipophilic and therefore attracts the ink; and the non-image area, which is hydrophilic, and repels the ink. The plate is dipped in a solution that binds to the non-image area, and then inked. In this way, the ink only adheres to the image, which is then transferred first to a rubber cylinder and then printed onto the paper.