To understand and to get the greater benefits of the new print technology, one must be also familiar with the customary printing technicalities and methodology, and how it is different from one another.
Litho printing is based on the principle that "water and grease do not mix" (P&D 2003), a process in which flexible aluminium or plastic printing plates are used. These printing plates are often having rough surfaces covered with photosensitive emulsion in which photographic negative of an image rest. After the plate's exposure to light, the emulsion produces a reproduction of the original image in reverse. The plate will then chemically treated to make the positive image sensitive to printing inks and later will be attach to printing press cylinders. There are two types of rollers; Water rollers are use to apply water on blank portions of the plate and ink rollers to cover the positive image area where the picture will appear. It is not possible to print these images directly on paper because the paper will become excessively wet. This is the reason why the plate rolls against a drum covered with rubber blanket to press away the water and accept the ink. Following this procedure, the paper can now safely roll against the blanket drum while the images transfer to the paper. This procedure is known as "offset" printing, where images are initially transferred to a rubber drum. ...Show more