Printing is a process for reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals.
It is use to making the impression on paper (or on other substance such as vellum) from inked type (or as the technique develops from plates, blocks or cylinders). From this type the most important aspect of printing is that it permits a large number of copies to be made of each seating of type.
Offset printing is a widely used printing technique. Offset printing is where the inked image is transferred (or “offset”) from a plate to a rubber blanket. An offset transfer moves the image to the printing surface. When used in combination with the lithographic process, a process based on the repulsion of oil and water; the offset technique employs a flat (planographic) image carrier. So, the image to be printed obtains ink from ink rollers, while the non-printing area attracts a film of water, keeping the non-printing areas ink-free.
Gravure printing is an intaglio printing technique, where the image being printed is made up of small depressions in the surface of the printing plate. The cells are filled with ink, and the excess is scraped off the surface with a doctor blade. Then a rubber-covered roller presses paper onto the surface of the plate and into contact with the ink in the cells. The printing cylinders are usually made from copper plated steel, which is subsequently chromed, and may be produced by diamond engraving; etching, or laser ablation .
As it name implies this printing technique relies on a screen, which is a woven piece of fabric. Certain area of the web is coated with the non-permeable material. In the remaining open spaces ink can be pushed through the mesh onto a substrate. The advantage of printing screen is that the surface of the recipient does not have to be flat and that the ink can be adhere to a wide range of material such as paper, textile, glass, ceramic, wood and metal.