A guide to litho printing

Litho printing is a method for printing which uses a metal plate or stone with a smooth surface. Invented in 1796 by the Bavarian author Alois Senefelder, it is a low-cost method which enables the possibility of publishing theatrical works that can be employed for artwork or to print text.

An Introduction to lithography

Lithography generally employs a drawn image or text onto an oily substance or wax, that is then applied to a plate of lithographic stone as the base to transfer the ink to a blank sheet of paper, which then produces a printed page. The image In contemporary offset lithography printing, the image is constructed of a polymer coating that is applied to an aluminium plate which is flexible. To then print the image, the flat surface of the stone plate is roughened, etched and then divided into hydrophilic regions that accept a coating of water, which repels the ink. This happens due to the fact that the surface tension is far greater on the greasy image, as this remains dry. The image or text can either be printed straight from the stone plate, or it can be offset, by moving the image onto a flexible sheet, thus enabling publication and printing. The principles of lithography Lithography employs simple chemical processes to produce an image. For example, the negative image is known as hydrophilic, or water-loving, while the positive part of the image is known as hydrophobic, or water-hating. So, when the plate is connected to a compatible printing water and ink mixture, the water will clean the negative image, while the ink gels with the positive image.

Using lithographic printing for professional use

The advantages of lithographic printing One of the major advantages of lithography is down to the fact that the soft rubber surface of the blanket produces an impression that is clear on a number of materials and paper surfaces. It is easily noticed due to the smooth print, in addition to its lack of serrated edges or ring of ink that is prevalent of photogravure or letterpress printing. Lithography has plate-printing solutions available for the use of short, medium and long press runs. Web press and sheet-fed presses are employed in lithography. Sheet-fed lithography Sheet-fed lithography is typically used for business brochures, posters, direct mail inserts, art reproductions, catalogues, greeting cards, packaging, printing advertising, and as a book printer. There are various sheet-fed lithography presses that can perfectly print on both sides of the paper, in one take. Digital print lithography is employed for newspapers, advertising literature, magazine, preprinted newspaper inserts, books and catalogues, all of which can also use colour printing.