By the end of the 2nd century CE, the Chinese apparently had discovered printing; certainly they then had at their disposal the three elements necessary for printing: (1) paper, the techniques for the manufacture of which they had known for several decades; (2) ink, whose basic formula they had known for 25 centuries; and (3) surfaces bearing texts carved in relief. Some of the texts were classics of Buddhist thought inscribed on marble pillars, to which pilgrims applied sheets of damp paper, daubing the surface with ink so that the parts that stood out in relief showed up; some were religious seals used to transfer pictures and texts of prayers to paper. It was probably this use of seals that led in the 4th or 5th century to the development of ink of a good consistency for printing.
A substitute for these two kinds of surfaces, the marble pillars and the seals, that was more practical with regard both to manageability and to size, appeared perhaps by the 6th century in the wood block. First, the text was written in ink on a sheet of fine paper; then the written side of the sheet was applied to the smooth surface of a block of wood, coated with a rice paste that retained the ink of the text; third, an engraver cut away the uninked areas so that the text stood out in relief and in reverse.
To make a print, the wood block was inked with a paintbrush, a sheet of paper spread on it, and the back of the sheet rubbed with a brush. Only one side of the sheet could be printed.
The oldest known printed works were made by this technique: in Japan about 764–770, Buddhist incantations ordered by Empress Shōtoku; in China in 868, the first known book, the Diamond Sūtra; and, beginning in 932, a collection of Chinese classics in 130 volumes, at the initiative of Fong Tao, a Chinese minister.
Invention of movable type (11th century)
About 1041–48 a Chinese alchemist named Pi Sheng appears to have conceived of movable type made of an amalgam of clay and glue hardened by baking. He composed texts by placing the types side by side on an iron plate coated with a mixture of resin, wax, and paper ash. Gently heating this plate and then letting the plate cool solidified the type. Once the impression had been made, the type could be detached by reheating the plate. It would thus appear that Pi Sheng had found an overall solution to the many problems of typography: the manufacture, the assembling, and the recovery of indefinitely reusable type.
In about 1313 a magistrate named Wang Chen seems to have had a craftsman carve more than 60,000 characters on movable wooden blocks so that a treatise on the history of technology could be published. To him is also attributed the invention of horizontal compartmented cases that revolved about a vertical axis to permit easier handling of the type. But Wang Chen’s innovation, like that of Pi Sheng, was not followed up in China.
In Korea, on the contrary, typography, which had appeared by the first half of the 13th century, was extensively developed under the stimulus of King Taejong, who, in 1403, ordered the first set of 100,000 pieces of type to be cast in bronze. Nine other fonts followed from then to 1516; two of them were made in 1420 and 1434, before Europe in its turn discovered typography.
Transmission of paper to Europe (12th century)
Paper, the production of which was known only to the Chinese, followed the caravan routes of Central Asia to the markets at Samarkand, whence it was distributed as a commodity across the entire Arab world.
The transmission of the techniques of papermaking appears to have followed the same route; Chinese taken prisoner at the Battle of Talas, near Samarkand, in 751 gave the secret to the Arabs. Paper mills proliferated from the end of the 8th century to the 13th century, from Baghdad and then on to Spain, then under Arab domination. Paper first penetrated Europe as a commodity from the 12th century onward through Italian ports that had active commercial relations with the Arab world and also, doubtless, by the overland route from Spain to France. Papermaking techniques apparently were rediscovered by Europeans through an examination of the material from which the imported commodity was made; possibly the secret was brought back in the mid-13th century by returning crusaders or merchants in the Eastern trade. Papermaking centres grew up in Italy after 1275 and in France and Germany in the course of the 14th century.
But knowledge of the typographic process does not seem to have succeeded, as papermaking techniques had, in reaching Europe from China. It would seem that typography was assimilated by the Uighurs who lived on the borders of Mongolia and Turkistan, since a set of Uighur typefaces, carved on wooden cubes, has been found that date from the early 14th century. It would be surprising if the Uighurs, a nomadic people usually considered to have been the educators of other Turco-Mongolian peoples, had not spread the knowledge of typography as far as Egypt. There it may have encountered an obstacle to its progress toward Europe, namely, that, even though the Islamic religion had accepted paper in order to record the word of Allah, it may have refused to permit the word of Allah to be reproduced by artificial means.
The invention of printing
Thus, the essential elements of the printing process collected slowly in western Europe, where a favourable cultural and economic climate had formed.
Xylography
Xylography, the art of printing from wood carving, the existence and importance of which in China was never suspected by Marco Polo, appeared in Europe no earlier than the last quarter of the 14th century, spontaneously and presumably as a result of the use of paper. It had been observed that paper was better suited than rough-surfaced parchment for making the impressions from wood reliefs that manuscript copyists used to reproduce the outline of ornamental initial capital letters.
The process was extended to the making of religious pictures. These at first appeared alone and later were accompanied by a brief text. As engravers became more skillful, the text finally became more important than the illustration, and in the first half of the 15th century small, genuine books of several pages, religious works or compendiums of Latin grammar by Aelius Donatus and called donats, were published by a method identical to that of the Chinese. Given the Western alphabet, it would seem reasonable that the next step taken might have been to carve blocks of writing that, instead of texts, would simply contain a large number of letters of the alphabet; such blocks could then be cut up into type, usable and reusable.
It is possible that experiments were in fact made along these lines, perhaps in 1423 or 1437 by a Dutchman from Haarlem, Laurens Janszoon, known as Coster. The encouraging results obtained with large type demonstrated the validity of the idea of typographic composition.
But the results were disappointing with regard to type destined for use for text of the usual size. The letters of the roman alphabet were smaller than Chinese ideograms, and cutting them from wood was a delicate operation. Moreover, type made in this way was fragile, and it wore out at least as quickly as blocks carved with a whole text. Further, since the letters were individually carved, no two copies of the same letter were identical any more than when the text was engraved directly on a wood block. The process, thus, represented no advance in ease of production, durability, or quality.
Metallographic printing (1430?)
Metallographic impression is more likely to turn out to be the direct ancestor of typography, although the record is far from clear. Several medieval craft guilds, notably the metal founders, the die-cutters, and goldsmiths and silversmiths, were familiar with the technique of using dies. Masters of this technique apparently realized that it could be applied to a process that would enable texts to be set in relief more quickly than by carving wood blocks, probably in three steps: (1) a set of dies, each bearing a letter of the alphabet, was engraved in brass or bronze; (2) using these dies, the text was struck letter by letter to form a mold on the surface of a matrix of clay or of a soft metal such as lead; (3) lead was then poured over the surface to form a small plate that, once hardened, would bear the text in relief.
The theoretical advantages of this process were that only one engraving per letter, that of the die, was required to make the letter as often as desired, and any two examples of the same letter would be identical, since they came from a single die; sinking the matrix and casting the lead were rapid operations; the lead had better durability than wood; and by casting several plates from the same matrix the number of copies printed could be rapidly increased.
Metallographic printing appears to have been practiced in Holland around 1430 and next in the Rhineland. Gutenberg used it in Strassburg (now Strasbourg, France) between 1434 and 1439.
But the experiments were not followed up because of problems created by the cast plates. It was difficult to strike each letter die with the same force and to keep a regular alignment, and, worse, each strike tended to deform the adjacent letter. It may well be that the major value of metallographic printing was that it associated the idea of the die, the matrix, and cast lead.
The invention of typography—Gutenberg (1450?)
This association of die, matrix, and lead in the production of durable typefaces in large numbers and with each letter strictly identical, was one of the two necessary elements in the invention of typographic printing in Europe. The second necessary element was the concept of the printing press itself, an idea that had never been conceived in the Far East.
Johannes Gutenberg is generally credited with the simultaneous discovery of both these elements, though there is some uncertainty about it, and disputes arose early to cloud the honour.
It is true that his signature does not appear on any printed work. If masterpieces such as the Forty-two-Line Bible of 1455 rather than the imperfect products of a nascent typography such as the donats of 1445 or the “Astronomic Calendar” of 1447–48 are attributed to him, this is because of deduction and historical and technical cross-checking. The basic assumption is that, since Gutenberg was by profession a silversmith, he would have retained the role of designer in an association set up at Mainz, Germany, with the businessman Johann Fust and Fust’s future son-in-law the calligrapher Peter Schöffer. The assumption is based solely on the interpretation of obscure aspects of a lawsuit that Gutenberg lost against his associates in 1455.
Apart from chronicles, all published after his death, that attributed the invention of printing to him, probably the most convincing argument in favour of Gutenberg comes from his chief detractor, Johann Schöffer, the son of Peter Schöffer and grandson of Johann Fust. Though Schöffer claimed from 1509 on that the invention was solely his father’s and grandfather’s, the fact is that in 1505 he had written in a preface to an edition of Livy that “the admirable art of typography was invented by the ingenious Johan Gutenberg at Mainz in 1450.” It is assumed that he had inherited this certainty from his father, and it is hard to see how a new element could have persuaded him to the contrary after 1505, since Johann Fust died in 1466 and Peter Schöffer in 1502.
The first pieces of type appear to have been made in the following steps: a letter die was carved in a soft metal such as brass or bronze; lead was poured around the die to form a matrix and a mold into which an alloy, which was to form the type itself, was poured.
Spectroscopic analyses of early type pieces reveal that the alloy used was a mix of lead, tin, and antimony—the same components used today: tin, because lead alone would have oxidized rapidly and in casting would have deteriorated the lead mold matrices; antimony, because lead and tin alone would have lacked durability.
It was probably Peter Schöffer who, around 1475, thought of replacing the soft-metal dies with steel dies, in order to produce copper letter matrices that would be reliably identical. Until the middle of the 19th century, type generally continued to be made by craftsmen in this way.
The typographer’s work was from the beginning characterized by four operations: (1) taking the type pieces letter by letter from a typecase; (2) arranging them side by side in a composing “stick,” a strip of wood with corners, held in the hand; (3) justifying the line; that is to say, spacing the letters in each line out to a uniform length by using little blank pieces of lead between words; and (4), after printing, distributing the type, letter by letter, back in the compartments of the typecase.
The Gutenberg press
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Documents of the period, including those relating to a 1439 lawsuit in connection with Gutenberg’s activities at Strassburg, leave scarcely any doubt that the press has been used since the beginning of printing.
Perhaps the printing press was first just a simple adaptation of the binding press, with a fixed, level lower surface (the bed) and a movable, level upper surface (the platen), moved vertically by means of a small bar on a worm screw. The composed type, after being locked by ligatures or screwed tight into a right metal frame (the form), was inked, covered with a sheet of paper to be printed, and then the whole pressed in the vise formed by the two surfaces.
This process was superior to the brushing technique used in wood-block printing in Europe and China because it was possible to obtain a sharp impression and to print both sides of a sheet. Nevertheless, there were deficiencies: it was difficult to pass the leather pad used for inking between the platen and the form; and, since several turns of the screw were necessary to exert the required pressure, the bar had to be removed and replaced several times to raise the platen sufficiently to insert the sheet of paper.
It is generally thought that the printing press acquired its principal functional characteristics very early, probably before 1470. The first of these may have been the mobile bed, either on runners or on a sliding mechanism, that permitted the form to be withdrawn and inked after each sheet was printed.
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Next, the single thread of the worm screw was replaced with three or four parallel threads with a sharply inclined pitch so that the platen could be raised by a slight movement of the bar. This resulted in a decrease in the pressure exerted by the platen, which was corrected by breaking up the printing operation so that the form was pushed under the press by the movable bed so that first one half and then the other half of the form was utilized. This was the principle of printing “in two turns,” which would remain in use for three centuries.
Improvements after Gutenberg
Several of the many improvements in the screw printing press over the next 350 years were of significance. About 1550 the wooden screw was replaced by iron. Twenty years later, innovators added a double-hinged chase consisting of a frisket, a piece of parchment cut out to expose only the actual text itself and so to prevent ink spotting the nonprinted areas of the paper, and a tympan, a layer of a soft, thick fabric to improve the regularity of the pressure despite irregularities in the height of the type.
See a working model of an early hand printing press
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About 1620 Willem Janszoon Blaeu in Amsterdam added a counterweight to the pressure bar in order to make the platen rise automatically; this was the so-called Dutch press, a copy of which was to be the first press introduced into North America, by Stephen Daye at Cambridge, Massachusetts in 1639.
About 1790 an English scientist and inventor, William Nicholson, devised a method of inking using a cylinder covered with leather (later with a composition of gelatin, glue, and molasses), the first introduction of rotary movement into the printing process.
The metal press (1795)
The first all-metal press was constructed in England in about 1795. Some years later a mechanic in the United States built a metal press in which the action of the screw was replaced by that of a series of metal joints. This was the “Columbian,” which was followed by the “Washington” of Samuel Rust, the apogee of the screw press inherited from Gutenberg; its printing capacity was about 250 copies an hour.
Stereotypy and stereography (late 18th century)
An increasing demand for printed matter stimulated the search for greater speed and volume. The concepts of stereotypy and stereography were explored. Stereotypy, used with notable success around 1790 in Paris, consisted in making an impression on text blocks of type in clay or soft metal in order to make lead molds of the whole. The stereotyped plates thus obtained made it economically possible to print the same text on several presses at the same time. The plates left the pieces of type in the form immediately available for further use and thus increased the rate at which they could be recycled.
A variation of stereotypy was the application, after 1848, of galvanoplastic metallization, in which process plates of thin metal lined with a base of lead alloy were made by electrolytic deposition of a coat of copper on a wax mold of the typeform.
Stereography aimed at bypassing the composition of the type in making the mold. Attempts to perfect the old metallographic method of preparing a clay matrix by stamping with dies brought no better results. In 1797 a variation was tried in which sets of copper matrices of each letter were made in large numbers. The matrices were then assembled according to the wording of the text, so that they covered the whole surface of the bottom of a mold in which the lead plate was then cast. Once the cast had been made, the matrices were available for further use.
Koenig’s mechanical press (early 19th century)
The prospect of using steam power in printing prompted research into means by which the different operations of the printing process could be joined together in a single cycle.
Friedrich Koenig’s mechanical platen press, 1811.
In 1803, in Germany, Friedrich Koenig envisaged a press in which the raising and lowering of the platen, the to-and-fro movement of the bed, and the inking of the form by a series of rollers were controlled by a system of gear wheels. Early trials in London in 1811 were unsuccessful.
Presses with a mechanized platen produced satisfactory results after the perfection, in the United States, of the “Liberty” (1857), in which the action of a pedal caused the platen to be held against the bed by the arms of a clamp.
Though Nicholson very early took out patents for a printing process using a cylinder to which the composed type pieces were attached, he was never able to develop the necessary technology involved.
The cylinder was in fact the most logical geometric form to use in a cyclical process. It was also the one capable of providing the greatest output. Given an equal amount of energy, the pressure exerted by a platen had to be spread over the whole of the surface to be printed, whereas the pressure exerted by a cylinder could be concentrated on the strip of surface actually in contact with the cylinder at any one instant.
A limited demonstration of the efficiency of the cylinder had been made as early as 1784 on a French press for books for the blind.
The first stop-cylinder printing machine, 1811, built by Friedrich Koenig and Andreas Bauer.
In 1811 Koenig and an associate, Andreas Bauer, in another approach to the rotary principle, designed a cylinder as a platen bearing the sheet of paper and pressing it against the typeform placed on a flatbed that moved to and fro. The rotation of the cylinder was linked to the forward movement of the bed but was disengaged when the bed moved back to go under the inking rollers.
In 1814 the first stop-cylinder press of this kind to be driven by a steam engine was put into service at the Times of London. It had two cylinders, which revolved one after the other according to the to-and-fro motion of the bed so as to double the number of copies printed; a speed of 1,100 sheets per hour was achieved.
In 1818 Koenig and Bauer designed a double press in which a sheet of paper printed on one side under one of the cylinders passed to the other cylinder, to be printed on the other side. This was called a perfecting machine. In 1824 William Church added grippers to the cylinder to pick up, hold, and then automatically release the sheet of paper.
The to-and-fro movement of the bed that was retained in these early cylinder presses constituted an element of discontinuity; to make the cycle completely continuous, not only would the platen have to be cylindrical but the typeform also. In 1844 Richard Hoe in the United States patented his type revolving press, the first rotary to be based on this principle. It consisted of a cylinder of large diameter, bearing columns of type bracketed together on its outer surface; pressure was provided by several small cylinders, each of which was fed sheets of paper by hand. This system gave speeds of more than 8,000 copies per hour; its only drawback was its fragility; faulty locking up of the forms caused the type to fall out of the cylinder.
This defect was remedied by applying stereotypy to the production; that is, forming curved plates by making an impression of the typeform on strong pasteboard, the flong, or mat, which was fixed against the inside surface of a rounded mold, which was injected with lead alloy. In France, from 1849 onward, experiments were conducted with this process; it was regularly used in London by the Times from 1856 onward and after 1858 was in general use.
But feeding the press with paper still remained outside the mechanized cycle. Mechanization of this step was accomplished by the use of a continuous roll of paper supplied on reels instead of sheets. Techniques for producing paper in a continuous roll had been known since the beginning of the century. The first roll-fed rotary press was made by William Bullock of the United States in 1865. It included a device for cutting the paper after printing and produced 12,000 complete newspapers per hour. Automatic folding devices, the first of which were designed by Bullock and Hoe, were incorporated into rotaries after 1870.
Later, numerous other types of curved stereotype plates were used on rotary presses. These included electrotype plates that are curved before being backed; rubber or plastic plates made by molding or by a photomechanical process; and metal wraparound plates made by photoengraving or electronic engraving.
Attempts to mechanize composition (mid-19th century)
Unlike the mechanization of the printing process, mechanization of the composition process was difficult to achieve in the 19th century. The invention of a compression mold in 1806 opened prospects for the mechanization of the production of type. In 1822 William Church of Boston patented a typesetting machine consisting of a keyboard on which each key released a piece of type of the corresponding letter stored in channels in a magazine. The pieces of type thus obtained had to be assembled by hand and the line justified. Church had avoided the problem of distribution and shown an intuition as to its solution by annexing to the magazine a device for constantly casting new pieces of type.
Numerous machines based on the same principle and with the further addition of a mechanism that placed the type pieces selected the right way round appeared in the course of the next 50 years. On one of these the more than 10,000 pages of the ninth edition of Encyclopædia Britannica were composed. These machines produced type at the rate of 5,000 to 12,000 pieces per hour, as opposed to about 1,500 by hand composition. But in all of them the type was simply delivered in a continuous row, which had to be divided into lines and justified.
These machines were completed by the introduction of a mechanical distributor, which was a sort of reverse compositor: pieces of type from lines that had been used passed before the operator, who pressed the corresponding key on his keyboard for the appropriate channel in the magazine to be opened up. The speed of mechanized distribution did not exceed 5,000 pieces of type per hour and was, thus, no faster than hand distribution.
Mechanization of letterpress composition faced two difficulties: first, justification, which required intelligent estimation of the size of spaces to be provided between words; and, second, the time taken during which the pieces of type were used for printing, which delay kept composition and distribution from being integrated into one cycle.
Typecasting compositors (1880s)
Linotype
Linotype
Finally, in the 1880s in the United States, German-born Ottmar Mergenthaler invented the Linotype, a typecasting compositor that cast a solid one-piece line, or slug, from movable matrices of each letter. Each of the matrices was individually notched so that it could return only to its proper slot in the magazine after use. Justification was carried out by inserting wedged spacebands between groups of matrices immediately after making up the words of a given line. Here the matrices rather than type pieces went through the four basic operations of letterpress composition; cast lead was used for printing. The Linotype can produce the equivalent of 5,000 to 7,000 pieces of type per hour.
In 1885, also in the United States, Tolbert Lanston invented the Monotype, which casts individual pieces of type for a line and justifies each line by a system of counting in units the width of the spaces taken up by the pieces of type. The matrices are indefinitely reusable, and the pieces of type, which are used only for the impressions, are returned to the caster. The contemporary Monotype typecaster is controlled by a ribbon of paper perforated on a separate keyboard. It can produce 10,000 to 12,000 pieces of type per hour.
In 1911 the American Washington I. Ludlow perfected a typecasting machine for the large display type that bears his name. The matrices are assembled by hand in a composing stick, which is then inserted above the opening of a mold; the matrices are also distributed by hand.
19th-century innovations
In the course of the 19th century several important innovations laid the foundation for a number of printing techniques that were not directly related to Gutenberg’s invention.
Reproduction of illustrations
The first process for reproducing illustrations was xylography, using woodcuts that printed in relief and that therefore could be combined with letterpress, the picture blocks and the pieces of type for texts being locked into the same form. As early as the second half of the 15th century, xylography faced competition from engraving on metal that printed by intaglio; the metal plate (copper, sometimes brass, zinc, and even steel after 1806), engraved with a tool (burin) or etched with acid, was inked and carefully wiped so that ink remained only in the incisions and was transferred to paper under pressure in a cylinder press derived from the rolling mill. Since the intaglio method of printing was not compatible with woodcut printing, sheets of text and of illustrations for the same book had to be printed separately.
Presses for printing curved intaglio-engraved plates were perfected during the 19th century with mechanized inking with the use of rollers and wiping with the use of revolving cloth bands or rotating disks covered with calico. Their printing capacity was limited.
As early as the end of the 18th century, however, intaglio printing had inspired a method for continuous printing of textiles by passing them under an engraved and inked cylinder from which excess ink had been removed by a scraper. In France in 1860 this technique was applied to printing paper for school-book covers. A solid copper cylinder was engraved not with continuous lines but with a multiplicity of tiny cavities in such a way that they retained the ink uniformly despite gravity, centrifugal force, and the action of the scraper. The process was suitable only for simple graphics.
Lithography: Senefelder (1796)
A third printing process that had undergone significant development was lithography, neither relief nor intaglio printing but based on the principle that water and grease will not mix. In 1796 Aloys Senefelder of Prague investigated the properties of a stone with a calcium carbonate base and a fine, homogeneous, porous surface. A design drawn on its surface with greasy ink, wetted with water and then brushed with ordinary ink, retained the ink only on the design. This could consequently be reproduced on a sheet of paper pressed against the stone. Senefelder also established that a design drawn on such a stone and printed on paper could be transferred to another stone in as many identical copies as desired, side by side, which made it possible to obtain several copies at a time by printing a single large sheet. He further established that a metal such as zinc had the same properties.
Senefelder envisaged a press in which the stone, secured to an undercarriage, was inked, covered with the sheet of paper with a sheet of pasteboard above it, and submitted to pressure. By 1850 the first mechanized lithographic press with a cylinder, flannel-covered rollers for wetting, and rollers for inking was perfected.
The fact that it was possible to replace the stone by a zinc plate that could be curved made it possible to build rotary presses (the first in 1868) in which the paper passed between the plate-bearing cylinder and the impression cylinder.
Photosensitivity: Niepce (1820s)
While searching for a means of automatically inscribing an image on a lithographic stone, then on a tin plate, in order to engrave it in intaglio, Joseph-Nicephore Niepce in the 1820s established that certain chemical compounds are sensitive to light. This marked the origins of photogravure and led to both the invention of photography (between 1829 and 1838) and the use of photographic processes for the printed reproduction of photographs.
In 1852 William Henry Fox Talbot, a British scientist and inventor, placed a piece of black cloth (tulle) between the object he wanted to reproduce (the leaf of a tree) and the photosensitive coating spread on a steel plate and obtained a picture that retained the fine mesh of the tulle. Consequently, etching with acid resulted not in an extensive and uniform erosion of an area but in tiny juxtaposed pits all over the photosensitive coating and varying in depth according to the degree of exposure. Talbot simultaneously had invented the screen and also had opened the way for a new development in intaglio printing: rotogravure.
The screen was perfected in the 1880s by substituting for the cloth two sheets of glass with uniform parallel lines that crossed perpendicularly. The screen made possible letterpress and lithographic reproduction of the full range of tones of a photographic document by using the effect of the diffusion of light through the mesh of its grid and converting the different intensity of tones into the different thicknesses of the printing surface.
Gravure and rotogravure (1890s)
The circular mechanization of intaglio engraving, meanwhile, came up against two associated difficulties: the need to engrave an infinite number of tiny cells and the need to engrave them directly onto a cylinder. There were problems, because the rubbing of the squeegee to remove excess ink excluded the use of a curved plate that would not have provided a uniform surface in the area in which it was attached, and it was not possible to get photosensitive solutions to adhere to a cylinder.
In 1862–64 J.W. Swan of Britain invented carbon tissue, paper coated with gelatin that can be rendered photosensitive and exposed to light before being applied to a metal surface of any shape.
In 1878 a Czech, Karl Klič (also spelled Klietsch), thought of copying a grid screen directly onto carbon tissue, which could be used to transfer the cells necessary for intaglio printing to a cylinder at the same time as the image to be reproduced. In 1895 Klič, with English colleagues, founded the Rembrandt Intaglio Printing Company, which published reproductions of pictures, on paper, by rotogravure. They kept their process a secret.
In a parallel way, patents for a slightly different process, in which the image to be reproduced was screened before making the impression on the carbon tissue, were taken out in Germany and the United States. But a workman from the Rembrandt Intaglio Printing Company emigrated to the United States in 1903 and there revealed Klič’s secret, and rotogravure, using his method, became widespread.
The 20th century
Beginning with the invention of the offset technique, the 20th century saw the steady development of innovations in the direction of mass production, speed, and economy.
Discovery of offset (early 20th century)
At the same time, lithography was undergoing a new evolution. After the first mechanical presses had been perfected, this process had developed along two lines: (1) printing on thin sheets of metal (for example, tinplate for packaging canned foods) using a transfer process (1878) in which the impression cylinder carrying the metal sheet to be printed did not come in contact with the stone but did with an intermediary cylinder covered with rubber, the blanket, which transferred the image from the stone to the metal; and (2) printing on paper, which was done only comparatively infrequently in the last years of the 19th century, on cylinder or rotary presses.
In 1904 at Nutley, New Jersey, an American printer, Ira W. Rubel, discovered that an image accidentally transferred from the plate cylinder of his rotary to the rubber blanket of the impression cylinder during a paper-feed stoppage could itself be used for printing and in fact produced a superior impression. Rubel and an associate constructed a three-cylinder press, the first offset press, the term since used to describe this increasingly popular printing device.
Dry offset (1920)
A few years later a problem arose in connection with printing the background of checks with a water-soluble ink to prevent forgeries. It was proposed that the lithographic plate of the plate cylinder be replaced with a stereotype plate or with a letterpress wraparound plate. This process, which combines the relief of letterpress, which does not require wetting, with the transfer of offset, is known as dry offset, or letterset. Its area of application is not limited to check backgrounds but is used in all areas of conventional printing.
Since 1950 another process has been developed, particularly in the United States. It combines rotogravure with the transfer of offset for printing wallpapers, plastic floor coverings, paper plates, and other products.
Colour printing
As early as 1457 a psalter, which Peter Schöffer signed but which some researchers now attribute to Gutenberg, included, in imitation of the contemporary illuminated manuscripts, paragraphs beginning with ornamental capital letters printed in two colours. This was accomplished by the use of two wood blocks that fitted one inside the other and could be separately inked.
Experiments to reproduce pictures in several colours on wood blocks were made in Germany in the 16th century. In the 17th century, different inks were applied to the different parts of the same engraved metal plate in such a way that all the inks were transferred to the paper in a single pressing. In 1719 a painter, Jacques-Christophe Le Blond, took out a patent in England for a process that used the three primary colours, blue, yellow, and red, and black for outlining shapes. Using a dense grid, he engraved four metal plates, bringing out on each plate the relative importance of the colour involved. The same sheet of paper then went through four successive impressions, each in a different colour.
In the 19th century the scientific definition of the principles of trichromatism, the enunciation of the fundamental theories of three-colour analysis and synthesis of colours by photography, the perfecting of coatings selectively sensitive to colours, and finally the use of the screen, instead of Le Blond’s hand-drawn grid, established the modern trichromatic technique (which becomes quadrichromatic when black is also used).
Automation of composition (after 1929)
The search for maximum efficiency had from the very beginning posed the problem of both the mechanization and the automation of composition. The Monotype system, with its separation of keyboard and caster, had constituted one approach to the solution, since the same caster could work at full speed when fed with perforated tapes produced on several keyboards.
The perfection of teletypesetter remote-control composing equipment in the United States by about 1929 permitted widespread application of the principle of separation of human function on the one hand and mechanized function on the other. The operator produces a tape on which each letter, symbol, and space is represented by a combination of perforations. A translator device reads the tape and, according to each combination of holes, orders the release of the necessary matrices for letters, signs, and justifying spaces. Machines casting one-piece fully spaced lines or slugs are able to produce more than 20,000 characters per hour.
Programmed composition (1950s)
The production of the perforated tape remained relatively slow, however, because of the time taken by the operator to decide where to make the division in a word at the end of a line. Eventually, in the second half of the 20th century, electronics provided the means of automatically making this decision.
In the 1950s the BBR system, named by the initials of three inventors in France, introduced programmed composition. Starting with a perforated tape continuously produced by the operator, a computer takes over the task of determining the length of lines, the places where words are to be divided according to grammatical rules and typographic usage, the integration of corrections, and even the presentation of the text according to the layout. The speed at which a final tape bearing this information can be produced is limited only by the performance of the perforator, which is the outlet device of the computer. Operating speeds have exceeded 300,000 characters per hour, or 10 times the capacity of the most modern slugcasting machines.
During the 1960s, perforated tape began to be replaced by magnetic tape, which is even more rapidly made, at a rate of about 1,000 characters per second, or 3,600,000 per hour. Although magnetic tape is useless for mechanical composers casting pieces of type or lines in lead, such speed is practical for other kinds of machines not burdened with the weight of lead and the inertia of their mechanical components.
Photocomposition
In preparing cylinders for rotogravure, offset plates, or letterpress wraparound plates, it is illogical to use the vast weight of lead in letterpress composition to produce a reproduction proof that will then be photographed. Before the end of the 19th century this circumstance led to consideration of machines for composing headings by photographing the images of the letters in succession. In 1915 the Photoline, a photographic equivalent of the Ludlow, assembled matrices of transparent letters in a composing stick in order to film each line of the heading.
First generation of phototypesetters: mechanical
The next idea to be tried involved the adaptation of existing typesetters by replacing the metal matrices with matrices carrying the image of the letters and replacing the caster with a photographic unit. The industrial application of this idea resulted in the Fotosetter (1947), a phototypesetter, and its variant the Fotomatic (1963), controlled by a perforated tape, both derived from the Intertype slugcasting machine; the Linofilm (1950), derived from the Linotype; and the Monophoto (1957), derived from the Monotype. Retaining the mechanical limitations of machines intended to shape lead, they could not achieve appreciably higher rates of performance. Photocomposition had to be rethought in functional terms. This approach was explored in Germany as early as the 1920s with the Uher typesetter, which had photographic matrices attached to a rotating disk.
Second generation of phototypesetters: functional
The second generation of phototypesetters is characterized by the maximum elimination of factors of inertia, the number of moving parts having generally been reduced to only two: a steadily revolving disk or drum carrying the photographic matrices and an optical device of prisms or mirrors allowing directional action on the beam of light provided by an electronic flashtube.
The first revolutionary application of this notion was the Lumitype, invented as the Lithomat in 1949 by two Frenchmen, René Higonnet and Louis Moyroud. Executed by phototypesetting, The Marvelous World of Insects was done on their machine in 1953. The first model had an attached keyboard. Later models with a separate keyboard printed more than 28,000 characters per hour.
A new Linofilm (1954), functional and electronic, was fitted with a device for selecting matrices by the action of the blades on the photographic shutter, producing 12 characters per second, or 43,200 per hour. The model that succeeded it (1965) is equipped with a drum and is capable of double the output. The Photon-Lumitype 713 (1957) also performs at the rate of 70,000 to 80,000 characters per hour. But at this speed the technique of using a rotary matrix case reaches its limit because of the problems posed by centrifugal force. The Lumizip 900 (1959) introduced a further revolutionary change by retaining as moving parts only the lens, which scans in a single movement the fixed series of light matrices so as to photograph at one time the whole line of 20 to 60 letters. Output reaches 200 to 600 characters per second, or more than 2,000,000 per hour; this machine required magnetic tape.
The first book composed with a Lumizip, the Index Medicus (1964), was as much of a landmark in the history of phototypesetting as the Forty-two-Line Bible had been in printing. Its more than 600 pages were completed in 12 hours. To produce the same work on a typecasting machine would have taken almost a year.
Third generation of phototypesetters: electronic
Magnetic tape was still faster than the fastest phototypesetters. To narrow this gap, a third generation of phototypesetters appeared in the 1960s, in which all mechanical moving parts were eliminated by omitting the use of light and therefore omitting the moving optical device responsible for operating in its field.
Cathode-ray-tube phototypesetters (RCA, Linotron, etc.) operate on a principle analogous to that of television: a narrow pencil of electrons analyzes an image matrix of each letter and commands the modulation of another pencil of electrons on a luminescent screen, which leaves an impression on photographic film. Performance exceeds 500 characters per second and even approaches 1,000, or more than 3,000,000 per hour.
Digiset, a German development that appeared in 1965, pushed the use of the electron to its logical conclusion by suppressing even the image matrix of the character, simply keeping the binary analysis of its design available in its magnetic memory; this is, in fact, all that is needed to modulate the pencil of electrons on the final screen. Phototypesetters of this kind (called alphanumerical) have theoretical performance rates exceeding 3,000 characters per second, or more than 10,000,000 per hour, and should be able to approach 30,000,000. Speeds such as these exceed the production rate even of magnetic tape. Consequently, to work at its most efficient output, such a typesetter must be directly connected to a computer with a similarly high rate of output.
Toward direct impression
The number of characters thus composed now approaches the number of characters printed on a press in the same time. The narrower this gap becomes, the more a still further revolutionary possibility looms—that of eliminating the press itself, since the typesetter can be made to deliver each page as quickly as the press would have. To accomplish this it would be necessary only to replace the photographic film that the photographer imprints when it is conventionally used with an inexpensive carrier capable of receiving an image in the same way without pressure.
Several pressureless printing processes have already been perfected. In 1923 an electrostatic onset system drew the ink of a cylindrical typeform to the paper by means of an electrical charge. In 1948 two Americans conceived another type of electrostatic printing in which the colouring agent is not ink carried on a typeform but a powder or a solution sensitive to the pull of an electric charge inscribed in a plate. This technique gave birth to xerocopy in office duplicating (see below Office printing) and, at the industrial level, to xerography for producing posters and maps.
Printing without pressure can also be accomplished on papers impregnated with photosensitive preparations and passed in front of a cathode-ray screen of a phototypesetter. The first experiment using this facsimile printing process was carried out in Japan in 1964 by the Mainichi shimbun, a Tokyo daily newspaper. The image of the newspaper page formed on the cathode-ray screen was transmitted by radio waves, as in television. It was reproduced using the electrostatic system, which does not require chemical treatment of the paper after its exposure.
Serigraphy and collotype: a renaissance
Parallel to the evolution of the three major printing processes, letterpress, offset, and lithography, various other techniques have experienced a similar evolution, which has allowed them to survive or to establish themselves in the course of the 20th century and to preserve or win a place in printing.
The art of reproducing a design by forcing ink through the mesh of a silk screen partly blanked out with a stencil plate (serigraphy) had been practiced by the Chinese and Japanese long before the invention of letterpress. In the 19th century the textile manufacturers of Lyon adopted it for printing textiles. In the 1930s in Great Britain and the United States the most varied materials (glass, wood, plastic) and even the most varied shapes (round objects, for example) were printed by serigraphy, which from a handcraft progressed to an industrial technique, with the screen prepared by photosensitization and printing carried out by semiautomatic or automatic machines.
Another process, patented in France in 1855 under the name Photocollography, was modified in 1865 under the name Phototypy (still used in France) and in Germany in 1868 under the name Albertypy (still used in Germany). This process used photosensitive substances not as agents in making plates for printing but to serve directly as the effective surface of such plates. Known elsewhere as the collotype process, the technique was in great favour between 1880 and 1914, was then neglected, and has recently been revived and mechanized for printing posters and transparencies in black and in colour.
Flexography is a letterpress process using rubber plates on the plate cylinder; it occupies a special place in printing on account of the fluidity of its inks. It was first patented in England in 1890, and it was perfected in Strassburg a few years later. Flexographic printing is particularly suited to relatively coarse surfaces (pasteboard, wrapping paper, plastic or metal film) but has also been adapted to newspaper and magazine printing. It can be carried out by sheet-fed machines but is chiefly used on powerful rotaries.
Three-dimensional printing (1960s)
In the 1960s a three-dimensional print was developed, essentially an illustration bearing two views, superimposed, of the same image taken from slightly different angles, on a transparent mount striped with a multitude of imperceptible parallel strips (Xograph process). On account of these strips, each eye, looking at the print from a different angle, sees only one image. The three-dimensional illusion is produced when this binocular vision is interpreted by the brain.
Office printing
The development of industry and commerce, in the 19th and 20th centuries, accompanied by an increase in administrative activity, created a demand for an abundance of printed information at various levels. In the field of office printing the first tool was the typewriter, perfected in 1867. Thereafter, machines appeared that would reproduce large or small numbers of copies of typewritten texts and, later, texts or illustrations of every kind. Some of these machines rely on techniques very close to those of conventional printing; others turned to original techniques that were in turn extended into modern printing. In 1881 in England appeared the stencil duplicator, basically employing the serigraphic technique. In 1900 a photocopying machine invented in France opened the way to facsimile printing. The offset printing process spread into the area of business printing with small offset duplicating machines; the simplified methods used for preparing plates for these machines eventually were adopted by industrial offset printers.
The application of the electrostatic printing process to xerocopy, perfected in 1938, has since been taken over by industry.
All the various processes of duplication and reproduction of documents make up reprography, a name bestowed during the first congress devoted to these techniques, which was organized at Cologne in 1963. Though its boundaries with conventional printing are poorly delimited, to the extent that reprography can compete with conventional printing when a medium number of copies are concerned, reprography nevertheless represents an original field. In response to the increased need for quality reprography, the typewriter has been improved since the 1950s and given the capability of providing justified composition suitable for conventional printing.
Modern printing techniques
Composition and typesetting
Mechanical composition and typesetting
In the first decades of the 20th century all type was set and composed into columns and pages by hand or by mechanical means. These methods are still widely used.
Letterpress composition by hand
The font, which constitutes a complete set of characters of a given typeface, with duplicate numbers of each letter in proportion to the frequency with which each is used, is stored in the compartments of a case; capital letters, proportionately less frequently called for, are in the upper compartments, whence their name, uppercase, and the small letters in the lower compartments, which are more easily accessible and whence their name, lowercase.
The typographer works standing in front of the case. His principal tools are the composing stick, a metal angle iron with one fixed end and a “knee” with a screw or lever for locking; the line gauge, a ruler graduated in units of typographic measurement; and tweezers.
He locks the knee of the composing stick at the justification; that is, at the length of the line to be composed. Against the inside edge of the stick he places a lead, a strip of nonprinting lead alloy that later enables him, using a second lead, to grip the finished line in order to remove it from the composing stick. Holding the composing stick in one hand, he uses the other to select the individual type characters from the case. He can tell by touching which way up they should go, thanks to a nick indicating the top or bottom of the body (the bottom in English-speaking countries and Germany; elsewhere, the top), and he places them side by side in the composing stick. Having completed the proper number of characters to fill the length of the line with a whole word or at the correct division in a word, he adds as necessary to the nonprinting pieces already in place to mark the spaces between the words until the exact justification is obtained.
Having composed and justified the line, the typographer takes it, gripped by its two leads between the thumb and forefinger of both hands, to place it in a galley, a wooden or metal tray with a raised edge on two or three of its sides.
Semimechanized composition
The Ludlow is considered a combination machine; though it automatically casts slugs, it is related to hand composition by the way the matrices are assembled. The matrices are bronze blocks bearing the letter or sign engraved in intaglio on their lower side and with two shoulders on their upper side.
The composer gathers them individually from the case, which is one of the drawers of a desk, and arranges them side by side in a special composing stick. This steel composing stick is hollowed out in the middle to receive the matrices supported on their shoulders with an adjustable stopscrew for fixing the length of the line. Justification is ensured by blank unengraved matrices in various sizes equally distributed between the words.
The caster resembles a steel workbench with a hollowed-out slot on its surface in which the composing stick is inserted with the matrices face down. A lever starts the casting process by turning on an electric motor. A mold with an opening rises and positions itself under the aligned matrices; a plunger in the melting pot containing the molten alloy forces enough alloy into the mold to cast one line; casting is completed in less than 10 seconds, the mold withdraws and releases the solidified line, and the lever, which releases the composing stick, rises automatically.
Since the body size of the font is a uniform size, the upper part of characters whose body size exceeds its measurement projects beyond each side and has to be supported, when it is being used, with leads.
Since the width of the slugs is also uniform, when shorter lines are being cast the composing stick is furnished with thick, blank matrices; once cast, the line is clipped off to the proper length. For longer lines, composing sticks are used with justifications in multiples of that of the mold. Fractions of the line are cast one after another and fit together exactly. The Ludlow is used especially for casting lines of large type for use as titles and subtitles, using typefaces varying from 12 to 144 points (one point equals 1⁄72, or 0.0138, inch).
The Ludlow caster is complemented by an Elrod caster. This automatically casts nonprinting leads and rules, narrow pieces of nonprinting alloy; both items come in various thicknesses.
Another type of mixed typecaster with manual assembly of the matrices is represented by the All-Purpose Linotype, a sort of Linotype from which only the casting part has been retained. It is used primarily in United States printing establishments. An Italian equivalent, the Nebitype, is used, though less widely, in Europe.
Mechanical composition: slugcasting typesetters
The Linotype and Intertype slugcasting typesetters produce lines of letterpress composition in a single operation, starting with the assembling of the movable matrices. The letter matrices are thin, brass 19 × 32-millimetre (0.7 × 1.3-inch) plates, with two ears and a system of 14 notches arranged in a V on the upper surface and two heels in their lower part. The letter is engraved in intaglio on the face surface; usually two copies of the same letter are superimposed (duplex matrices)—one normal, or roman, the other a variant, either italic (sloping design) or boldface (stronger design). Thus, their thickness varies according to the letter and the body of the character.
The set of matrices is stored in a magazine, a flat, trapezoidal metal box consisting of 90 channels in which the matrices are aligned one behind the other, duplicates of 20 or 24 for each letter or sign, lying face down, resting on an ear and a heel.
Blanks are introduced into the line in two ways: either by using unengraved blank matrices, included in the magazine in three standard sizes, or by using spacebands designed to ensure justification.
The operator sits in front of a keyboard with 90 keys, corresponding to the channels in the magazine, on the left the lowercase letters, on the right the uppercase letters, in the middle the small capitals, numbers, and various symbols. A special bar operates the release of spacebands.
Slugcasting typesetters function as follows: (1) Touching a key releases the matrices, which are brought in proper order on a conveyor belt to a composing stick made of slide-bars and held by their ears. The spacebands, which are stored directly above the composing stick, fall into place between the words. (2) When the matrices and spacebands in the composing stick visibly take up the amount of space planned for the length of the line, the operator completes the line, either with a whole word or by dividing the last word, and pushes a lever to move the line. Since the remaining operations are done automatically he can go on to set the next line. (3) The assembled matrices and spacebands are moved three times in succession: vertically upward on the composing stick; sideways to the left on a transfer slide rest; vertically downward on an elevator that puts them in front of the opening of a mold mounted on a cogwheel called a mold wheel, connected to an electric melting pot containing the molten lead alloy. (4) A justifying hammer forces the long pieces of the spacebands upward, forcing them to separate by equal spaces until all the matrices and spacebands are locked between two steel jaws fixed at the precise justification of the line. A piston plunges into the melting pot and forces the alloy into the mold to cast the line. (5) While the mold wheel rotates three-quarters of a revolution and the solidified line is finished to its exact letterpress height before it is ejected into a galley, the matrices and spacebands are again moved upward by the elevator. (6) They are pushed to the right toward a triangular bar bearing 14 grooves corresponding to the 14 notches in the matrices. (7) Raised by a catcher arm, this bar removes the matrices, which are caught by their notches; the unnotched spacebands are released and immediately return to the place where they are stored. (8) When the catcher arm is at its highest position, the matrices are pushed to the right toward another triangular bar with 14 grooves along its length and flush with the top part of the magazine; this is the distributor bar. (9) The matrices move along the distributor bar until at a certain point the arrangement of grooves ceases to provide support for the notches, which of course are different for each letter or sign. Each letter’s matrix is then released at the opening of its own channel in the magazine.
The automatic cycle of the typesetter is controlled by several large cams mounted on a single shaft driven by an electric motor.
Modern typesetting machines are equipped with several magazines of varying type sizes that can be used alternately. Some so-called double-distribution machines permit two magazines to be used at once by pressing a supplementary key.
The performance of recent models has been improved by accelerating the revolution of the matrices, intensifying the cooling system of the mold, and increasing the number of molds on the mold wheel to six.
The slugcasting typesetter, which furnishes solid, easy to handle, composed type, is particularly suited to printing newspapers. It has the disadvantage that to correct any error, however trivial, the whole line must be recomposed.
The All-Purpose Linotype is a combination manual and automatic machine that retains only the casting part of the Linotype. Special matrices, solidly rectangular or with notches, ears, and heels, are assembled by hand in a composing stick. Justification is done with blank matrices of various sizes. The line of matrices, held by the composing stick, is placed against two set squares fastened to the bedplate of the machine and manually pushed on a slide rest, which takes it to the elevator. The elevator places the matrices in front of the opening to the mold for the casting operation, which delivers the slug. The matrices are then distributed by hand.
Mechanical composition: slugcasting typesetters
The Linotype and Intertype slugcasting typesetters produce lines of letterpress composition in a single operation, starting with the assembling of the movable matrices. The letter matrices are thin, brass 19 × 32-millimetre (0.7 × 1.3-inch) plates, with two ears and a system of 14 notches arranged in a V on the upper surface and two heels in their lower part. The letter is engraved in intaglio on the face surface; usually two copies of the same letter are superimposed (duplex matrices)—one normal, or roman, the other a variant, either italic (sloping design) or boldface (stronger design). Thus, their thickness varies according to the letter and the body of the character.
The set of matrices is stored in a magazine, a flat, trapezoidal metal box consisting of 90 channels in which the matrices are aligned one behind the other, duplicates of 20 or 24 for each letter or sign, lying face down, resting on an ear and a heel.
Blanks are introduced into the line in two ways: either by using unengraved blank matrices, included in the magazine in three standard sizes, or by using spacebands designed to ensure justification.
The operator sits in front of a keyboard with 90 keys, corresponding to the channels in the magazine, on the left the lowercase letters, on the right the uppercase letters, in the middle the small capitals, numbers, and various symbols. A special bar operates the release of spacebands.
Slugcasting typesetters function as follows: (1) Touching a key releases the matrices, which are brought in proper order on a conveyor belt to a composing stick made of slide-bars and held by their ears. The spacebands, which are stored directly above the composing stick, fall into place between the words. (2) When the matrices and spacebands in the composing stick visibly take up the amount of space planned for the length of the line, the operator completes the line, either with a whole word or by dividing the last word, and pushes a lever to move the line. Since the remaining operations are done automatically he can go on to set the next line. (3) The assembled matrices and spacebands are moved three times in succession: vertically upward on the composing stick; sideways to the left on a transfer slide rest; vertically downward on an elevator that puts them in front of the opening of a mold mounted on a cogwheel called a mold wheel, connected to an electric melting pot containing the molten lead alloy. (4) A justifying hammer forces the long pieces of the spacebands upward, forcing them to separate by equal spaces until all the matrices and spacebands are locked between two steel jaws fixed at the precise justification of the line. A piston plunges into the melting pot and forces the alloy into the mold to cast the line. (5) While the mold wheel rotates three-quarters of a revolution and the solidified line is finished to its exact letterpress height before it is ejected into a galley, the matrices and spacebands are again moved upward by the elevator. (6) They are pushed to the right toward a triangular bar bearing 14 grooves corresponding to the 14 notches in the matrices. (7) Raised by a catcher arm, this bar removes the matrices, which are caught by their notches; the unnotched spacebands are released and immediately return to the place where they are stored. (8) When the catcher arm is at its highest position, the matrices are pushed to the right toward another triangular bar with 14 grooves along its length and flush with the top part of the magazine; this is the distributor bar. (9) The matrices move along the distributor bar until at a certain point the arrangement of grooves ceases to provide support for the notches, which of course are different for each letter or sign. Each letter’s matrix is then released at the opening of its own channel in the magazine.
The automatic cycle of the typesetter is controlled by several large cams mounted on a single shaft driven by an electric motor.
Modern typesetting machines are equipped with several magazines of varying type sizes that can be used alternately. Some so-called double-distribution machines permit two magazines to be used at once by pressing a supplementary key.
The performance of recent models has been improved by accelerating the revolution of the matrices, intensifying the cooling system of the mold, and increasing the number of molds on the mold wheel to six.
The slugcasting typesetter, which furnishes solid, easy to handle, composed type, is particularly suited to printing newspapers. It has the disadvantage that to correct any error, however trivial, the whole line must be recomposed.
The All-Purpose Linotype is a combination manual and automatic machine that retains only the casting part of the Linotype. Special matrices, solidly rectangular or with notches, ears, and heels, are assembled by hand in a composing stick. Justification is done with blank matrices of various sizes. The line of matrices, held by the composing stick, is placed against two set squares fastened to the bedplate of the machine and manually pushed on a slide rest, which takes it to the elevator. The elevator places the matrices in front of the opening to the mold for the casting operation, which delivers the slug. The matrices are then distributed by hand.
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