The production of multiple copies of a document, book, etc., by the use of plates or other surface to transfer an impression to a substrate For much of the history of printing, letterpress (or "relief") was employed, but advancements since the nineteenth century have produced a wide variety of printing processes.
HISTORY OF PRINTING
The history of printing begins in a parallel course with that of moveable type. Although Johann Gutenberg, a goldsmith from Mainz, Germany (c. 1400:c. 1468), is regarded as having invented both moveable type and the printing press, the former dates back to eleventh-century China, and the latter to eighth-century Japan and ninth-century China. Between 1058 and 1061, Pi Sheng used clay, and later tin, to create type. The nature of the Chinese language (the lack of a true alphabet and the presence of more than 40,000 characters) made the invention and practical use of moveable type a near impossibility. Pi Sheng's type was not widely used, and didn't catch on in the East until a couple hundred years later. Metal type was invented in 1403 in Korea, primarily due to the dearth of hardwood necessary to create workable blocks of type, and was quickly endorsed and adopted by the Korean emperor T'ai Tsung as an aid to government and the preservation of civilization.
The idea of using raised blocks of wood to create an impression on a substrate (initially clay) derived from seals (used in impressing signatures). (The Chinese word for "print" is the same as that for "seal.") In the second century C.E., classical texts were stamped into stone; around the fifth century, ink was applied to the blocks. The earliest known printed book is the "Diamond Sutra," printed by Wang Chieh in C.E. 868. Many other books, most in roll form but one in the cut-sheet form we are familiar with today, were found that date from around the same time. Shortly thereafter, the idea of printing was adopted by religious adherents to promote their doctrines, and prayers, hymns, and other ecclesiastical materials were widely duplicated and disseminated. The other primary use of printing, dating from around 969 or earlier, was the production of playing cards. In the tenth century, the emperor agreed to (and financed) the printing of the Chinese classics, which led to a widespread revival of learning and education during the time of the Sung Dynasty (known as the Sung Renaissance). Also in the tenth century, printing was enthusiastically applied to the production of paper currency, which had the effect of introducing to China the concept of inflation.
The invention of block printing had a dramatic effect on Chinese culture and the democratization of knowledge; by 972, five thousand volumes of the Buddhist canon had been printed, and hundreds of volumes of Dynastic histories appeared soon thereafter, followed by encyclopedias, dictionaries, as well as compilations and anthologies of literature. There was, in a word, a riot of scholarship. The downside, however, is that due to a prohibition on the use of printing for commercial (i.e., money-making) purposes, all printed texts were given away gratis by the government. This helped stifle the further development of printing technology; moveable, metal type, created in Korea, had a brief popularity, then died away. The prevalence of moveable type could have been effected by the adoption of a simplified, twenty-four character alphabet devised by King Sajong of Korea, but interest in things Chinese (rather than Korean) prevented this. Typesetting (as we now know it) only became popular in China after Gutenberg's invention and the principles and techniques of Eastern typography were introduced by missionaries, after having first been carried from Korea to Europe, probably by Arab traders. What goes around comes around.
In Europe, there is evidence (albeit inconclusive) that printing utilizing moveable type was first practiced in the 1430s in Haarlem, Holland, by Laurens Coster. If that was the case, it didn't catch on, as the next recorded Dutch use of the technology was in 1470, when German printers set up a press in Utrecht.
The birth of the printing press in Europe can be traced back to the demand for religious indulgences. Following the ebbing of the Black Death in the late fourteenth century, there was a great economic boom, and general sense of revelry in Europe. As a result of all the "moralistic infractions" going on at the time, there was a great need for indulgences (basically, religious documents absolving sinners of their sins). Indulgences (for which there was big money for those providing and writing them) could be obtained at any of a variety of religious shrines and popular pilgrimage spots throughout Europe. Also to be obtained at these pilgrim "conventions" were any number of religious artifacts—trinkets, special mirrors with which one was supposed to catch the image of oneself standing before the shrine, and other sorts of "souvenirs." Makers and sellers of these items pursued their craft with a vigor and determination similar to that employed by carnival or fair hawkers of today. One particular maker of these artifacts had borrowed a significant amount of money from his business partners to invest in the manufacture and selling of these items at a big pilgrim convention in Aachen in the mid-1400s. Unfortunately, in 1439, he discovered to his horror that he got the year of the festival wrong and missed it. Heavily in debt to his partners, he assured them that he had been secretly working on something else that was likely to be a goldmine (literally). He was a goldsmith from Mainz, Germany, born Johann Gensfleisch (the German word for "gooseflesh"); understandably, he preferred to use his mother's maiden name, Gutenberg. Although he wasn't the first person in Europe to print from moveable type, he was the first to make it practical, and devised the metal punch, metal matrix to receive the punched—or engraved—metal letters, numbers, and punctuation marks, and a mold to hold the appropriate metal characters in a line for printing. (The printing press itself was essentially a modified press used in papermaking.) In 1450, Gutenberg mortgaged his printing press to a goldsmith named Johann Fust. The first things that were printed—dating from 1454, or perhaps even as early as 1451—were indulgences. In 1455, Gutenberg, who had not yet repaid his mortgage to Fust, was sued. Unable to pay, Gutenberg's press was confiscated by Fust, and the printing work was carried on by Peter Sch?ffer, Gutenberg's typesetter. (Actually, it is believed by many that the important developments of moveable type were devised by Sch?ffer.) In 1456, Gutenberg borrowed more money and set up another printing press, on which he produced the first printed book—the "Gutenberg Bible." The spread of printing was accelerated by Adolf of Nassau's 1462 invasion of Mainz. The printers, fleeing the city, spread the art throughout Europe. As for Gutenberg, he ended up in Eltville, set up another press, and, after several years of unending financial crises, died in 1468.
It is probably small consolation to Gutenberg that the printing press had an infinitely profound effect on European culture, and was in fact the goldmine he had promised it would be (for everyone but him, alas). At the time, however, there was enough demand for such a process in Europe that someone was likely to have invented it. (The Plague had killed off many of the scribes, and those who were left were expensive.) The speed at which the printing press spread throughout Europe was lightning-fast; within fifty years there were over 200 presses operating in Europe, and eight million books printed. The effect of the printing press was profound; William Caxton's introduction of the press into England in the 1460s resulted in not only the professional career of Geoffrey Chaucer, but also the standardization of the English language (in other countries, other vernaculars became standardized as well; printers must have realized that the bulk of the book-buying public didn't know Latin). The Protestant Reformation was accelerated by the use of printing; Martin Luther had used printing to disseminate his problems with the Catholic church. The printing and consequent rediscovery of ancient Greek and Roman texts resulted in the Renaissance. The literacy rate of the European population soared, as more people had access to books, which were far more inexpensive than books produced by scribes. (Interestingly, great advances in the manufacture and availability of eyeglasses appeared shortly before the printing press.) Whereas before printing, knowledge and learning were the privilege of a rare few (such as monks and university scribes), many people now had access to it. Writers who had previously been unable to get their work disseminated (scribes, in particular monks, would frequently fail to copy manuscripts they felt were heretical, and many manuscripts that came their way were erased and the paper "recycled") could flourish.
The earliest printers were only interested in reproducing texts cheaply and quickly, and had also wanted to preserve the look of the older handwritten manuscripts. Soon, however, printers such as Johann and Wendelin da Spira, Nicolas Jenson, and many others began to design distinctive "typefaces" specifically for book printing, called "roman" typefaces. The great Venetian printer Aldus Manutius not only printed the first "pocket editions" but also pioneered the use of italic type (as a means of fitting more characters per page and thus making the books cheaper to produce; eventually, italics came to be used merely for emphasis or titles; see Type).
The next four hundred years consisted of improvements on and mechanization of the typesetting and printing processes. Type was inserted character-by-character into a composing stick, which comprised a line of type. The characters from the composing stick were then transferred en masse to a metal or wooden tray called a galley. After the galley was proofed, it was broken down into pages, and running heads, folios, etc., were added. Each page of type was then locked up, to be sent for platemaking or to the pressroom if the material was going to be printed directly from type. Presses at that time were flat-bed, or platen, presses in which the type was locked onto a flat platen and the substrate was pressed over it, either sheet by sheet, or, later, by a rotating cylinder. In 1725, Scottish printer William Ged invented a process for making plates from locked-up type. It was refined and officially named stereotyping shortly afterward by Firmin Didot. In stereotyping, locked-up type is covered with a wet paper or mat, and pressure applied to stamp the impression of the type in the mat. The paper or mat is allowed to dry. The mat is then removed, and placed in a casting machine, where molten metal is added to cast an entire page of type as a single plate.
In 1811, the German printer Friedrich K?nig adapted the printing press to steam power, allowing the duplication of greater volumes of printed material. In 1846, the American printer Richard Hoe created a cylinder-type press (in contrast to the flat-bed type previously employed), in which the type could be locked into place on a rotating cylinder. In 1869 English printers began using curved stereotype plates on cylinder-based presses, which replaced the assembled type forms. These developments were the most significant advances in printing technology towards the attainment of greater volume and speed. In the late 1800s, machine composition of type was developed by Ottmar Mergenthaler (who invented the linotype, or a machine for producing type line by line, rather than character by character), and Tolbert Lanston (who invented the monotype, or a device that uses a typewriter-like keyboard to punch holes in a paper tape, which is then fed back through a casting machine to automatically determine what characters get cast). Later developments such as the varityper also improved and expedited the setting of type. (See Type.)
MAJOR PRINTING PROCESSES
The printing process utilized for most of the history of printing is what we could today term "letterpress"; a raised image or text area (the moveable type of Gutenberg's day, stereotype plates of the 1800s, or modern letterpress plates) is inked and the image transferred to a surface, primarily paper. Letterpress printing, although still used today, has been largely replaced by offset lithography, or a descendent of letterpress printing known as flexography (see below). (See Letterpress.)
'Lithography'. Lithography, or printing utilizing a flat surface on which an oil-based ink-receptive image area and a water-receptive non-image area are the same height and kept separate by the chemical repulsion between oil and water, was invented in 1796 by Alois Senefelder, a Bavarian playwright searching for a way to cheaply produce his plays. He discovered that a certain type of Bavarian limestone was ideally suited to the process. (The word "lithography" itself is derived from Greek words meaning "stone writing.") He devised the first lithographic press, and eventually zinc and aluminum plates replaced the stones, and around 1905 Ira Rubel was the first to realize that a rubber blanket produced a higher-quality image than did the stone plates. Many had noticed this (a rubber blanket initially covered the impression cylinder on lithographic stone presses, and feeding problems often resulted in accidentally printing on the blanket, which then erroneously transferred to the paper) but Rubel was the first to construct a press that used a rubber blanket as an image carrier. And so was born the offset press. New refinements and technological refinements have made offset lithography the dominant form of printing in the world. (See Lithography and Offset Lithography.)
'Gravure'. The early precursors to true gravure printing go back to 9th century China, but became prevalent in the West around the middle of the 15th century. Early gravure—or intaglio—methods of printing commonly comprised engraved wood or metal blocks into which ink was poured and then transferred to a substrate. In 1879, Viennese printer Karel Klic adapted such disparate elements as line-engraving, etching, mezzotinting, etc., to a printing process, called gravure printing. The gravure printing process uses a metal cylinder engraved with the text or design matter to be printed. (The engraved portions of the gravure cylinder are called cells.) The cylinder rotates in an ink fountain, where ink collects in the depressed cells and is wiped off the outside of the cylinder. As the paper (or other surface) is brought into contact with the cylinder, the ink is transferred out of the cells onto the substrate by capillary action (or a transfer of a liquid from one place to another by virtue of the surface tension of the liquid) generated by pressure of the substrate on the surface of the cylinder. The gravure process can also be used to print at high speeds on fast-moving paper webs, a process called rotogravure. (See Gravure.) A variety of intaglio printing (considered as a separate process from gravure) is copperplate printing, such as that commonly used for currency. (See Copperplate Printing.)
'Flexography'. The youngest of the major printing methods, flexography is a variety of rotary letterpress printing utilizing flexible rubber or plastic plates to transfer a highly liquid ink to a wide variety of substrates, primarily plastic films, corrugated board, and other types of packaging material. Flexography has its origins in the early twentieth century and developments in the vulcanization of rubber and the consequent invention of rubber stamps. The process of making a metal relief plate (as in letterpress), making a depressed mold from it, and making a relief rubber plate was used initially to print on surfaces—such as corrugated board—that did not yield good results with conventional letterpress processes. Early flexo printing—then called aniline printing—used aniline dyes. The invention of synthetic rubbers and the anilox roller (used to effectively meter and transfer ink to the plate) was a boon to the process, and it began to have more and more applications. The proliferation of plastic packaging materials proved to be ideal substrates for aniline printing. However, aniline dyes were banned by the FDA after it was found that the dyes were toxic. Although aniline printers had by then been using different types of less toxic colorants, the name still remained, and in 1952 the name of the process was, after a contest held by the Packaging Institute, officially renamed "flexography." Flexography today is primarily used for various types of plastic packaging, but also has applications in printing on paper, as well. (See Flexography.)
'Screen Process'. Screen process printing is also known as screen printing, silk screening, and serigraph, and derives from older practices of stencil printing. The screen process was devised in Germany and Scotland in the late 1800s. In 1907, Englishman Samuel Simon created a process of screen printing utilizing a cut stencil of the intended design mounted on a finely-woven silk screen, a brush being used to force the ink through the screen in the cut-out areas of the stencil. (This was a direct descendent of an older pochoir method of stencilling.) In 1914, American John Pilsworth devised a system for the silk screening of banners, and until the late 1930s silk screening was used primarily for commercial purposes, eventually becoming favored among artists. Silk screening today still retains the simplicity of earlier forms of it; a hand-cut or photographically-produced stencil is mounted on the bottom of a fine mesh screen, which has been stretched taut on a wooden frame. A fairly viscous ink (formerly paint) is placed on the screen, and a squeegee pulls the ink down over the stencil, where it prints the design onto the intended substrate (commonly textiles, such as T-shirts and other decorative materials such as posters). Screen process printing is not used for other traditional types of printing, such as books, newspapers, etc. (See Screen Process.)
Other varieties of printing are being constantly developed, in particular electrostatic printing and xerography, printing methods involving the attraction of electrostatically-charged pigment particles (called toner) to an oppositely-charged metal drum. Such printing methods are utilized in photocopying machines and computer laser printers. (See Electrostatic Printing.) Another variety of printing common in computer markets is ink jet printing, in which tiny electrically-charged droplets of ink are aimed at the substrate, and as they travel they are deflected to the proper position on the paper by means of a charged deflector plate. (See Ink Jet Printing.)
Each printing process has different ink and paper requirements to generate the best possible printed image which is, after all, the goal of any printing process. (See Paper and Papermaking: Printing Requirements and Ink: Printing Requirements.)