Known as “mother of civilization”, the art of printing is the technology of producing printed images according to the original script or picture. In 1900 a scroll of Diamond Sutra was discovered in Dunhuang grottos, which was printed at the 9th year of Xiantong in the reign of Emperor Yi (868) in the Tang Dynasty. It consists of seven adhered sheets with a total length of 533 centimeters, clearly printed, showing a superb carving skill. It is the earliest printed matter existent now in the world. The earliest carved plate printed matter with a definite date now existent in Europe is the portrait of St. Christopher in the South of Germany, later than the printed scroll found in China by about 600 years.
Before the invention of printing, the circulation of books depended totally on hand-written copies of manuscripts. This was not only a slow process but was liable to mistakes. The first method of printing in China was the seals in relief or intaglio. but their small size prevented them from printing many characters at a time. Then stone tablets were cut in intaglio, inked and impressions taken off, first on silk and later on paper when it was invented, but the impressions were less clear white characters on the black background. In the Spring and Autumn Period and Warring States Periods, seal-engraving and stone-tablet rubbing were very much in vogue.
This, then, led in the Sui Dynasty to the practice of engraving writing or pictures on a wooden board~ smearing ink on it and then printing on pieces of paper page by page. The page was printed when the paper was removed. This was called block printing, combining the two methods used for seals and stone rubbings. In the Tang Dynasty, this technology was already very popular and was introduced successively to countries like Korea, Japan, Vietnam, the Philippines and Iran. Although with this method the speed of printing was much higher than before, the block printing had its drawbacks. That is all the boards became useless after the printing was done and a single mistake in carving would cause a whole board to be wasted. And it was time- consuming, ted, for it would take several years to finish making the blocks for a thick book.