The Three Stage Print Process

The printing process has three stages—prepress, press, and binding or postpress.
Description
The printing industry prints products ranging from newspapers, magazines, and books to brochures, labels, newsletters, postcards, memo pads, business order forms, checks, maps, T-shirts, and packaging. The industry also consists of establishments that provide related services to printers, such as embossing, binding, finishing, and prepress services. Commercial lithographic printing establishments, which print newspaper inserts, catalogs, pamphlets, and advertisements, make up the largest segment of the industry, accounting for about 40 percent of employment and 32 percent of total establishments. Establishments offering primarily digital printing, which is the most technologically advanced method of printing constitutes the smallest segment of the industry—about 3 percent of total employment. Much of the work of this segment is characterized by low volume, often done by very small shops or freelance workers. Another segment of the printing industry is quick printing. Quick printing establishments generally provide short-run printing and copying with fast turnaround times.

Printing is a large industry composed of many shops that vary in size. More than 2 of every 3 printing shops employ 10 or fewer workers. These small printing shops often are referred to as “job shops,” because what they print is determined by the needs of their customers.

There are five printing methods that use plates or some other form of image carrier— lithography, letterpress, flexography, gravure, and screen printing. Plateless or nonimpact processes, such as electronic, electrostatic, or inkjet printing, are used mainly for copying, duplicating, and specialty printing, usually in quick printing or in-house print shops.

Lithography, which uses the basic principle that water repels oil, remains the dominant printing process in the industry. Lithography lends itself to computer composition and the economical use of color, accounting for its dominance. Letterpress prints images from the raised surfaces on which ink sits; the sunken surfaces do not show up on the paper. The raised surfaces are generated by means of casting, acid etching, or photoemulsion. In the future, flexography, and gravure to a lesser extent, are expected to be more widely used than at present. Flexography produces vibrant colors with little ruboff, qualities valued for newspapers, directories, and books, which are its biggest markets. Gravure’s high-quality reproduction, flexible pagination and formats, and consistent print quality have won it a significant share of packaging and product printing and a growing share of periodical printing.

Another type of printing included in this industry is screen printing, also known as commercial screen printing. This method is used to print designs on clothes and other fabric items, such as caps or napkins. In response to environmental concerns, printers increasingly use alcohol-free solutions, water-based inks, and recycled paper.

The printing industry, like many other industries, continues to undergo technological changes, as computers and technology alter the manner in which work is performed. Many of the processes that were once done by hand are becoming more automated. Technology’s influence can be seen in all three stages of printing: Prepress, preparation of materials for printing; press, the actual printing process; and postpress or finishing, the folding, binding, and trimming of printed sheets into final form. The most notable changes have occurred in the prepress stage. Instead of cutting and pasting articles by hand, workers now produce entire publications on a computer, complete with artwork and graphics. Columns can be displayed and arranged on the computer screen exactly as they will appear in print, and then printed. Nearly all prepress work is becoming computerized, and prepress workers need more training in computers and graphic communications software. Printing processes today use scanners to input images and computers to manipulate and format the graphic images prior to printing. Digital printing also is transforming prepress operations as well as the printing process. It eliminates much of the lengthy process in transferring print files to the printing press by directly transferring digital files to an electronically driven output device bypassing most prepress operations.

The History of Printing

This idea was developed upon by the Koreans and Johannes Gutenberg of Germany during the 1400s to create printers with movable types made of metal. The advances made printing far more efficient and by 1474 Englishman William Caxton was publishing books in the English language.

Today printing presses are used to communicate to a mass audience in the form of books, newspapers, magazines and circulars. In addition, printing computer hardware allows businesses, organizations and individuals to publish a huge range of things cheaply and quickly.

Processes
There are three main printing processes: Letterpress or relief printing - Letterpress is the very first type of printing and was for a long time the only method used. The developments of other methods have made this method seem less efficient. This method involves printing using inking areas of raised type which are held into a frame and locked into place.

They are then inked with a roller. Paper is then covered over the inked type and rolled using a second roller. Lithography or planographic printing - Unlike relief printing, planographic printing uses a flat-sufaced printing plate.

It is based on an artistic method of drawing images using wax crayons on a flat limestone surface. Originally, ink was applied to the surface (but did not stick to the stone) and this was pressed against a piece of paper.

The simpler method was developed using aluminium plates instead of stone and was originally used for music scores. The type image was developed on to a sheet of film and through a photographic process it was transfered to the aluminium plate to create printing and non-printing areas.
Gravure or intaglio printing - This method is the exact opposite to the letterpress method and was originally done by hand as engravements.

The image is cut into a polished metal sheet. The surface is inked and whiped leaved a depression of ink. Sheets of paper are squeezed into the gaps by the press. A more complicated method involved cutting the design into a wax covering and applying acid to develop etchings.

The current method used is called the photogravue process because it involves applying a photographic image to the plate and developing very small holes in which the ink is held

For more definition of printing, and other industries please go to the following URL where this text was taken from: http://open-site.org/Business/Publishing_and_Printing/Printing/