Printing refers to the technology of transferring ink from original documents such as text, pictures, and photos to the surface of paper, textiles, leather, and other materials through processes such as plate making, ink application, and pressure to reproduce the content of the original documents in bulk. There are various forms of printing, the most common of which are traditional offset printing, screen printing, and digital printing.

Printing is divided into three stages:

Pre press → refers to the pre printing work, generally including photography, design, production, typesetting, output film sampling, etc;

Printing → refers to the process of printing finished products through a printing machine during the mid-term of printing;

Post press → refers to the post printing work, generally including post processing of printed materials such as gluing (film covering), UV coating, oil coating, etching, hot stamping, embossing, mounting, binding, cutting, etc. It is mostly used for promotional and packaging printed materials.

Printing is a technology for copying original text and image information. Its biggest feature is that it can reproduce the text and image information on various substrates in a large and economical way. It can be said that its finished products can also be widely circulated and permanently preserved, which is incomparable to other copying technologies such as movies, TV, and photography.

The production of printed materials generally involves five processes: selection or design of the original manuscript, original production, plate drying, printing, and post press processing. That is to say, first select or design an original manuscript suitable for printing, then process the graphic and textual information of the original manuscript to produce an original version (usually called a positive or negative image negative) for printing or engraving plates, and then use the original version to produce a printing plate for printing. Finally, install the printing plate on the brush machine, use the ink conveying system to apply ink to the surface of the printing plate, and apply pressure by a pressure machine. The ink is then transferred from the printing plate to the substrate. The large number of printed sheets copied in this way, after post printing processing, become finished products suitable for various purposes. Nowadays, people often refer to the design of the original manuscript, image and text information processing, and plate making as pre press processing, while the process of transferring ink from the plate to the substrate is called printing. The completion of such a printed product requires processes such as pre press processing, printing, and post press processing.