Printing

Printing (from Lat. imprimere, O. Fr. empreindre), the art or practice of transferring by pressure, letters, characters or designs upon paper or other impressible surfaces, usually by means of ink or oily pigment. As thus defined, it includes three entirely different processes: copperplate printing, lithographic or chemical stone-printing, and letterpress printing. The difference between the three lies in the nature or conformation of the surface which is covered with the pigment and afterwards gives a reproduction in reverse on the material impressed. For the nature and method of preparing these surfaces see respectively Engraving (and allied articles), Lithography and Typography. In copperplate printing the whole of the plate is first inked, the flat surface is then cleaned, leaving ink in the incisions or trenches cut by the engraver, so that, when dampened paper is laid over the plate and pressure is brought to bear, the paper sinks into the incisions and takes up the ink, which makes an impression in line or lines on the paper. In lithographic printing the surface of the stone, which is practically level, is protected by dampening against taking the ink except where the design requires. In letterpress printing the printing surface is in relief, and alone receives the ink, the remainder being protected by its lower level. Before the invention of typography, pages of books, or anything of a broadside nature, were printed from woodcuts, i.e. blocks cut with a knife on wood plankwise, as distinct from wood engravings which are cut with a burin on the end grain, a more modern innovation. These woodcuts, like the lithographic or engraved surface, served one definite purpose only, but in typography the types can be distributed and used again in other combinations.

The term " printing " is often used to include all the various processes that go to make the finished product; but in this article it is properly confined to " press-work," i.e. to the work of the printing-press, by which the book, newspaper, or other printed article, when set up in type and ready as a surface to be actually impressed on the paper, is finally converted into the shape in which it is to be issued or published.

History of Printing-press.  Before dealing with modern machinery it will be necessary to consider the historical evolution of the printing-press, especially since the middle of the 19th century, from which point printing machinery has developed in a most remarkable manner.

It is not clear how the first printers struck off their copies, but without doubt Gutenberg did use at an early period in his career a mechanical press of some kind, which was constructed of wood. In fact he could not have produced his famous forty-two line Bible without such aid.

The earliest picture of a press shows roughly the construction to have been that of an upright frame, the power exerted by a movable handle, placed in a screw which was tightened up to secure the requisite impression, and was loosened again after the impression was obtained. The type pages were placed on a fiat bed of solid wood or stone, and it was quite a labour to run this bed into its proper position FIG. i. - Blaeu's Wooden Hand-press.

under the hanging but fixed horizontal plane, called the platen, which gave the necessary impress when screwed down by the aid of the movable bar. This labour had to be repeated in order to release the printed sheet and before another copy could be struck off. This same press, with a few modifications, was apparently still in general use till the early part of the 17th century, when Willem Janszon Blaeu (1J71-1638) of Amsterdam, who was appointed map maker to the Dutch Republic in 1633, made some substantial improvements in it. Our first authority on printing, Joseph Moxon, in his Mechanick Exercises, as Applied to the Art of Printing (vol. i., 168 3), says, " There are two sorts of presses in use, viz. the old fashion and the new fashion," and he gives credit to Blaeu for the invention of the new and decidedly improved press (fig. 1).

Blaeu's improvement consisted of putting the spindle of the screw through a square block which was guided in the wooden frame, and from this block the platen was suspended by wires or cords. This block gave a more rigid platen, and at the same time ensured a more equal motion to the screw when actuated by the bar-handle. He also invented a device which allowed the bed on which the type pages were placed to run in and out more readily, thus reducing the great labour involved in that part of the work of the older form of press, and he also used a new kind of iron lever or handle to turn the screw which applied the necessary pressure. The value of these various improvements, which were in details rather than in principles, was speedily recognized, and the press was introduced into England and became known as the " new fashion." From this it will be observed that in a general way there had only been two kinds of wooden presses in use for a period of no less than three hundred and fifty years, and when the work of some of the early printers is studied, it is marvellous how often good results were obtained from such crude appliances.

The iron press (fig. 2) invented by Charles, 3rd earl Stanhope (1753-1816), at the end of the 18th century was a decided advance on those made of wood. Greater power was obtained at a smaller expenditure of labour, and it allowed of larger and heavier surfaces being printed. The chief points of the iron press consisted of an improved application of the power to the spindle. The main part of it was FIG. 2. - The Stanhope Iron Hand-press.

complete press to stand upon. The staple was united at the top and bottom, but the neck and body were left open, the former for the mechanism and the latter for the platen and the bed when run in preparatory to taking the impression. The upper part of the staple, called the nut, answered the same purpose as the head in the older kind of wooden press, and was in fact a box with a female screw in which the screw of the spindle worked. The lower portion of the neck was occupied by a piston and cup, in and on which the toe of the spindle worked. On the near side of the staple was a vertical pillar, termed the arbor, the lower end of which was inserted into the staple at the top of the shoulder - the upper end passing through a top-plate, which being screwed on to the upper part of the staple held it firmly. The extreme upper end of the arbor, which was hexagonal, received a head, which was really a lever of some length; this head was connected by a coupling-bar to a similar lever or head, into which the upper end of the spindle was inserted. The bar by which the power was applied by the pressman was fixed into the arbor, and not into the spindle, so that the lever was the whole width of the press, instead of half, as in Blaeu's wooden press, and it was better placed for the application of the worker's strength. There was also another lever to the arbor head in addition to that of the spindle head; and lastly, the screw itself was so enlarged that it greatly increased the power. The platen was screwed on to the under surface of the spindle; the table or bed had slides underneath which moved in, and not on, ribs as in the older form of press, and was run in and out by means of strips of webbing fastened to each end and passed round a drum or wheel. As the platen was very heavy the operator was assisted in raising it from the type-forme by a balance weight suspended upon a hooked lever at the back of the press. This somewhat counterbalanced the weight of the platen, raised it after the impression had been taken, and brought the barhandle back again to its original position, ready for another pull.

The Stanhope press, which is still in use, was soon followed by other hand-presses made of iron, with varying changes of details. The most successful of these were the Albion and Columbian presses, the former of English manufacture, and the latter invented (1816) by an American, George Clymer (1754-1834), of Philadelphia.

The Albion press (fig. 3), which was designed by Richard Whittaker Cope, was afterwards much improved upon by John Hopkinson (1849-1898). It is still used where hand printing prevails, and it was this form of press which was employed by William Morris at his famous, but short-lived, Kelmscott Press, the upright frame or staple, of iron; the feet of this staple rested upon two pieces of substantial timber dovetailed into a cross, which formed a base or foundation for the in the production of many sumptuous books, the most celebrated of which was the Chaucer, a large folio volume, illustrated by Sir Edward Burne-Jones. The chief characteristics of the Albion are its lightness of build and its ease in running; the pull is short, the power great, and the means whereby it is attained so simple that the press does not readily get out of order. It is easily taken to pieces for cleaning, and readily re-erected. The power is obtained by pulling the bar-handle across, which causes FIG. 3. - Payne & Sons' Albion Hand-press.

an inclined piece of wedge-shaped steel, called the chill, to become perpendicular; in so doing the platen is forced down, and the impression takes place at the moment the chill is brought into a vertical position. On the return of the bar the platen is raised by a spiral spring, placed in a box and fixed at the head of the press. The larger sizes of these presses usually print a sheet of double crown, measuring 30X20 in.

Although the Columbian is not so much in demand as the Albion, it is still employed for heavy hand-work because of its greater stability and power. This power is acquired by a very massive lever, moving on a pivot bolt in the top of the near side of the staple, and passing across the press to the further side of the frame, at which end the power is applied through the coupling-bar by a bar-handle working from the near side. The platen is attached to the centre of the lever by a square bar of iron, and its vertical descent is assured by two projecting guides, one from each cheek; it is then raised from the type-forme, and the iron bar carried back by two levers - the one attached to and above the head and weighted with the eagle; the other behind the press, attached to the arm to which the coupling-bar is fixed, and which also has a weight at the end. The great power of this press adapts it to the working of large and solid formes in printing, but it is somewhat slower in action than the Albion press, which is both lighter in construction and quicker in working.

The average output of the modern hand-press, when all is made ready for running, is about two hundred and fifty impressions per hour. This number, it should be said, is the product of two men who work together as " partners." One inks the type-forme and keeps a sharp look-out for any inequality of inking, and sees generally that the work is being turned out in a workmanlike manner. The other lays on the sheet to certain marks, runs the carriage in under the platen, and pulls the barhandle across to give the necessary impression. He then runs back the carriage and takes out the printed sheet, which he replaces by another sheet, and repeats the different operations for the next impression. During the interval between taking off the printed sheet and laying on the next one his partner inks the type surface with a roller which carries just sufficient ink properly distributed to preserve uniformity of " colour." Having dealt with hand-presses, we must now go back to the end of the 18th century, when the first experiments were made to devise some mechanical means of producing larger printed sheets, and at a quicker rate. In England the broad distinction between " presses " and " machines " is generally considered to rest in the fact that the former are worked by hand, and the latter by steam, gas or electricity; and the men who work by these two methods are called respectively " pressmen " and " machine minders " or " machine managers." But in America the terms " presses " and " pressmen " are universally applied to machines and the men who operate them. For the purposes of this article presses and machines are used as synonymous terms.

Various schemes had been propounded with a view of increasing the output of the hand-press, and in 1790 William Nicholson (1753-1815) evolved his ideas on the subject, which were suggestions rather than definite Cylinder  inventions. Nicholson was not a printer, but, as he was an author and editor, it is presumed that he had some knowledge of printing. His proposals were to print from type placed either on a flat bed or a cylinder, and the impression was to be given by another cylinder covered with some suitable material, the paper being fed in between the type and the impression cylinder, and the ink applied by rollers covered with cloth or leather, or both. While Nicholson's schemes did not bear any practical result they certainly helped others later on. His suggestion to print from type made wedge-shaped (that is, smaller at the foot and wider at the top) to allow of its being so fixed on a cylinder that it would radiate from the centre and thus present an even printing surface, was adopted later by Applegath and others, and really was the first conception of printing on the rotary principle which has now been brought to such perfection.

It was left to Friedrich Ktinig (1774-1833), a German, to produce the first really practical printing machine. His invention was to print type placed on a flat bed, the impression being given by a large cylinder, under which the type passed, but his inking appliances were not satisfactory. He induced the proprietor of The Times (London) to take two of these machines, and in 1814 that newspaper was printed with steam power at the rate of i roo impressions per hour, a great advance on the number produced up to that time. Both Nicholson's and Kijnig's machines printed only one side at a time - the second or backing printing being a separate and distinct operation - but they really embodied the general principles on which all other machines have been constructed or modelled.

It will be understood that Nicholson's theories were to print both from the flat and from type arranged in circular or cylinder form. These two principles are defined as reciprocating, for the flat bed which travels backwards and forwards; and rotary, for that which continuously revolves or rotates. Konig's invention was a reciprocating one.

Two other classes of presses of somewhat different design were largely in operation in the middle of the r9th century - the " double platen," which still printed only one side at each impression from each end, and the " perfecting machine," which was made with two large cylinders and printed from two typeformes placed on separate beds. Although the latter machine turned out sheets printed on both sides before it delivered them (hence its name), the second impression was still a distinct operation. The double platen press was somewhat analogous to the hand-press, both the type beds and impressions being flat. A machine of this kind, if it printed a sheet of double demy, which measures 35 X 221 in., was about 13 ft. in length, and the platen itself, of very massive construction, was placed in the centre. This platen had a perpendicular motion, being guided in grooves and worked by a connecting rod fixed to a cross beam and crank, which acquired its motion from the main shaft. There were two type beds and two inking tables, which travelled backwards and forwards, and one platen only, situated in the middle of the machine, which in turn gave the needful impression as the type-formes passed underneath. The sheets were laid or fed to certain marks between the frisket and tympan, and when these were closed together the carriage was propelled under the platen and the impression was given to that portion of the machine, while at the other end another sheet was being fed in ready to receive its impression in due course.

It was once thought that the finest work could not be produced by a cylinder impressing a surface in the progress of its reciprocating motion, but that it was likely to give a slurred or blurred impression. This is why machines of flat construction were so long employed for the best class of work. But cylinder presses are now made so truly turned, and geared to such nicety, that this idea no longer prevails. The cylinder press is able to produce generally quite as good work as the double platen, its speed is much greater, and it requires a smaller amount of power to drive it.

The perfecting machine has had a great vogue, and has been much improved from time to time, especially in America, though the two-revolution machine in recent years superseded it, whether temporarily or not being still uncertain. We shall deal with it more fully below in relation to the modern and more complicated class of machinery; and this also applies to the ordinary stop or single cylinder, and small platen machines, both of which have been in use many years, and are still in demand.

Before the general introduction of rotary machines which print from curved stereotype plates from an endless web or reel Type of paper (see below), several other presses of a revol- Revolving ving character were made, to some extent based on Nicholson's ideas. The first printing surface used was ordinary type, because the difficulty of curving the stereotype plates had not been surmounted. This type was fixed, both in vertical and in perpendicular positions, upon a cylinder, round which rotated other cylinders, which held and compressed the sheets against the larger one, which also revolved and carried the printing surface. These machines were made to print several sheets at a time, and were called four-, six-, eightor ten-feeders, according to the number of sheets fed in and printed. They necessitated a great deal of labour, because each feed required a separate layer-on and taker-off besides the superintending printer, and other hands to carry away the sheets as fast as they accumulated at the different taking-off boards. Besides, these sheets all had to be folded by hand. In this class of machine various improvements were made from time to time by different manufacturers, each profiting by the experiences of the others, and two kinds of such revolving presses may now be given as examples.

After many experiments Augustus Applegath (1789-1871) in 1848 constructed for The Times (London), a machine which was an eight-feeder, built entirely on the cylindrical principle, the cylinders placed not in a horizontal but in a vertical position. The type was fixed on a large cylinder, and instead of the printing surface presenting a complete circle, the different columns were each arranged so as to form a polygon. Around this large type cylinder were eight smaller ones, all upright, for taking the impression for each of the eight sheets fed in separately, and rollers were so arranged as to apply the ink to the type as it passed alternately from one impression cylinder to the other. The sheets were laid in from eight different feed-boards, placed horizontally, and they passed through tapes, when they were seized by another series of tapes and then turned sideways between their corresponding impression and type cylinder, thus obtaining sheets printed on one side only. The impression cylinder then delivered the sheets separately (still in a vertical position) into the hands of the boys employed as takers-off. The results from this press were, at the time, considered fairly satisfactory, the number of copies (about 8000) printed per hour from one type-forme having been materially increased by the employing of the eight different stations to feed the sheets in, all of which in turn were printed from the same single type surface.

About 1845 Robert Hoe & Co. of New York, and subsequently of London, had constructed, to meet the increased demands of newspapers, the " Hoe Type Revolving Machine," one good point of which was an apparatus for securely fastening in the type on a large central cylinder fixed horizontally. This was accomplished by the construction of cast-iron beds, one for each separate page (not column, as in Applegath's machine). The column rules were made tapering towards the feet of the type, and the type was securely locked in on these beds so that it could be held firmly in the required position to form a complete circle, thus allowing the cylinder to revolve at a greater speed than Applegath's, which was polygonal. Around the large type cylinders were placed the smaller impression cylinders, the number of these being governed by the output required. Hoe's first presses were four-feeders, but as many as ten feeds were supplied, as in the case of the two presses built to replace the Applegath machine for The Times, each of which produced about 2000 impressions from each feed, making a total of 20,000 per hour, printed on one side, or from two machines 20,000 sheets printed on both sides. As will be observed, the only differences in principle between these two type revolving machines were in the positions of the respective cylinders, and the fixing of the type to form a printing surface.

It was Sir Rowland Hill who first suggested the possibilities of a press which should print both sides at once, from a roll or reel of paper. This was about 1825, but it was William A. Bullock (1813-1867) of Philadelphia who in 1865 invented the first machine to print from a continuous web of paper. This machine had two pairs of cylinders, that is, two type or stereotype cylinders, and two others which gave the impression as the web passed between. The second impression cylinder was made somewhat larger so as to give a greater tympan surface, to lessen the off-set from the side first printed. In his machine the stereotype plates were not made to fill the whole periphery of the forme cylinders so as to allow of the sheets being cut before printing, a difficulty w'iich the first machines did not satisfactorily overcome. The sheets were severed by knives placed on the cylinders, and when cut were carried by grippers and tapes; and delivery was made by means of automatic metal fingers fixed upon endless belts at such distances apart as to seize each sheet in succession as it left the last printing cylinder. These presses were not at first reliable in working, especially in the cutting and delivery of the sheets after printing, but were finally so far improved that the Bullock press came into quite general use. The inventor was killed by being caught in the driving belt of one of his own presses.

Modern Presses.  The machines invented during the second half of the 19th century and still in general use, are best classified as follows: - I. The iron hand-press, such as the Albion or the Columbian, used for the pulling of proofs, or for the printing of limited editions de luxe. 2. Small platen machines (worked by foot or tion  power) used for the printing of cards, circulars and small jobbing or commercial work.

3\. Single cylinder machines (in England generally called " Wharfedales "), usually built on the " stop " cylinder principle, and printing one side of the sheet only.

4\. Perfecting machines, usually with two cylinders, and printing or " perfecting " both sides of a sheet before it leaves the machine, but with two distinct operations.

5\. Two-revolution machines, which, although with but one cylinder, have largely superseded perfecting machines, as their output has been increased and the quality of their work compares favourably with that of the average two-cylinder.

6\. Two-colour machines, usually made with one feed, that is, with only one cylinder, but with two printing surfaces, and two sets of inking apparatus one at each end of the machine. Occasionally these machines are made with two cylinders.

7\. Rotary machines, printing from an endless web of paper from curved stereotype or electrotype plates, principally used XXII. 12 for newspaper or periodical work. They are made to print upon a single reel, or upon two, four, six or even eight reels, in both single or double widths, i.e. two or four pages wide.

The hand-press has already been sufficiently described, and we may proceed to deal with the other classes.

The small but useful platen machine (fig. 4) is very largely employed in those printing-houses that make commercial work a speciality. The smaller machines can be worked with the foot, but if the establishment is equipped with power it is customary to gear them for driving. The larger machines require power. As its name implies, the type bed and impression platen are both flat surfaces as in the hand-press, but as they are self-inking and are easily driven, the average output is about moo copies per hour, and but one operator is required, whereas two men at a handpress can produce only 250 copies in the same time. In design these platen presses usually consist of a square frame with a driving shaft fixed horizontally across the centre of it. This shaft is attached to a large fly-wheel which gives impetus to the press when started and assists in carrying over the impression when the platen is in contact with the printing surface. The type-forme is usually fixed in an almost vertical and stationary position, and it is the platen on which the sheet is laid which rises from the horizontal position to the vertical in order to give the necessary impact to produce a printed impression from the typeforme. Practically this platen is, as it were, hinged at the off side, nearest the type bed, and its rise and fall is effected by the use of FIG. 4. - The Golding Jobber Platen two arms, one on each side Machi, of the platen, which derive ne an eccentric motion from cams geared in connexion with the shaft. When the sheet is printed and the platen falls back to the horizontal the operator removes it with one hand and with the other lays on a fresh sheet. Generally the larger of these machines will print a sheet up to 21 X 16 in.

The modern single or " stop " cylinder, quite different in construc- Wharfe= tion from the old single cylinder machines, largely suc dale" ceeded the double platen machine. The principle of the cl . stop cylinder was really a French invention, but it has Machines  been more commonly adopted in Great Britain, where the machines are known as " Wharfedales " (fig. 5). They are much used for the printing of books and commercial work. The average production is about woo copies per hour. The type bed travels with a reciprocating motion upon rollers or runners made of steel, the bed being driven by a simple crank motion, starting and stopping without much noise or vibration. All the running parts are made of hard steel. The cylinder is " stopped " by a cam motion while the bed is travelling backward, and during this interval the sheet to be printed is laid against the " marks," and the gripper closes on it before the cylinder is released, thus ensuring great accuracy of lay, and consequent good register. After the impression is made the sheet is seized by another set of fingers and is transferred to a second and smaller cylinder over the larger one, and this smaller cylinder or drum delivers the sheet to the " flyer," or delivery apparatus, which in turn deposits it upon the table. The inking arrangements are usually very good, for, by a system of racks and cogs which may be regulated to a nicety, the necessary distribution of ink and rolling of the printing surface runs in gear with the travelling type bed or coffin. All the accessories for inking are placed at the end of the machine, the ink itself being supplied from a ductor, which can be so regulated by the keys attached to it as to let out the precise amount of pigment required. The ink passes to a small solid metal roller, and is then conveyed by a vibrating roller made of composition to a larger and hollow metal cylinder or drum which distributes the ink for the first time. This revolves with the run of the machine and at the same time has a slight reciprocating action which helps the distribution. A second vibrating composition roller conveys the ink from this drum to the distributing table or ink slab, on which other rollers, called distributors, still further thin out the ink. As the type bed travels, larger composition rollers, called inkers, placed near the cylinder, adjusted to the requisite pressure on the type, pick up the necessary amount of ink for each impression and convey it to the type as it passes under them. Usually three or four such rollers are required to ink the forme.

The perfecting machine is so named because it produces sheets printed on both sides or, in technical language, " perfected." This operation is performed by two distinct printings. This perfecting class of machine has been in use a great many years, Machines.  although both the stop-cylinder and the two-revolution press have to some extent superseded it. It is perhaps best adapted for the printing of newspapers or magazines having circulations that do not require rotary machines intended for long runs. Although some perfecting machines have been made with one cylinder only, which reverses itself on the old " tumbler " principle, they now are made with two cylinders, and it is with this class that we are particularly concerned. There are various makes of perfecting machines of which the Dryden & Foord is shown in fig. 6; among the best recent typed is the Huber Perfecter.

Although the two-type beds have a reciprocating motion, as in the ordinary one-sided press, the two cylinders rotate towards each other. The frame of the machine, owing to the fact that it contains two carriages and a double inking apparatus, is long, the exact size depending on the size of the sheet to be printed. Close to the large cylinders are the inking rollers, which take the necessary amount of ink, each set from its own slab as it passes under, and these rollers convey the requisite ink to the printing surface as the forme-carriage runs under its own cylinder. The distinctive feature is the ingenious manner in which the sheets are printed first on one side, and then on the other. This is performed by carrying them over a series of smaller cylinders or drums by means of tapes. The pile of sheets ?

:Zan! ' '?  ?l"?????W Platen Jobbing Machines.  to be fed in stands on a high board at one end. The sheet is laid to its mark and is conveyed round an entry drum; thence it is carried round the first impression cylinder, and under this, moving at the same speed as the cylinder, is the type bed containing the inner of broad tapes which lie on the laying-on board and are fastened to a small drum underneath it. This drum has a series of small cogs which move the web or tapes in the same direction. The sheet is laid to a back mark on the tapes, and is propelled between two rollers s FIG. 6. - Dryden & Foord's Perfecting (two-cylinders) Machine.

forme already inked. The paper then receives its impression on the first side. In the older type of machine it 'is next led up to the right- ' hand one of the two reversing drums, which are placed above the large printing cylinders, and over which it passes with the printed side downwards. It is then brought under the second or left-hand drum, and so on to the other large impression cylinder, with the blank side of the sheet exposed to the type of the outer forme on the table underneath. Thus it will be seen that the sheet is reversed in its travel between the first and second large cylinders which give the impression. The sheet is then finally run out and delivered in the space between the two large cylinders, and laid on the delivery board - usually with the aid of flyers. In the more recent type of direct into the machine. Another variety employs grippers somewhat after the manner of the ordinary single cylinder. The AngloFrench perfecting machine is one of that class. As a rule most double-cylinder presses produce on an average about moo copies per hour, printed both sides.

The two-revolution machine is another one-cylinder machine built on the reciprocating principle. Its speed is greater than the stop cylinder (it may be geared to produce from 1500 to Two  copies per hour, printed one side only). The Revolution  Miehle (fig. 7), which is of American design but now made Machines.  also in Great Britain, is a good example of this kind of machine and is much used, especially for illustrated work. It has FIG. 7. - The Miehle Two-revolution Cylinder Machine.

perfecting machines the sheet is fed directly into grippers, change taking place when grippers on each cylinder meet, the outer forme grippers taking the sheet from the inner forme grippers.

This is a general description of the principles on which these machines are built, but, as in other classes, there are many variations in details. For example, there are the drop-bar, the web and the gripper methods of feeding these presses. In the first case a bar descends upon the paper after it is laid to point marks, and this bar, having a rotary motion, runs the sheet between a roller and a small drum into the machine. The web arrangement consists of a series the high over-feedboard, and the taking-off apparatus is automatic but on a different plan from that of the ordinary Wharfedale, the sheets being carried over tapes with the freshly-printed side uppermost, thus preventing smearing; they are then carried on to the heap or pile by the frame or long arms placed at the end of the machine. A recent feature of this machine is the tandem equipment, whereby two, three or even four machines may be coupled together for colour work. Only one layer-on is required and register is obtained automatically throughout.

The principle of the two-revolution press is that the cylinder always rotates in the same direction, and twice for each copy given, once for the actual impression, and again to allow of the return of the forme-carriage in its reciprocating action. This also allows time for the feeding in of the next sheet to be printed. Among other advantages claimed for this press one is that the movement which governs the action of the type bed in reversing is so arranged that the strain which sometimes occurs in other reciprocating machines is considerably reduced; another is that the registering or correct backing of the pages on the second side in printing is uncommonly good; but this depends much upon the layer-on. In many of the old kinds of two-revolution machines, owing to the cylinder being geared separately from the type bed, it was apt to be occasionally thrown out, but in the Miehle, for instance, it is only out of gear in reversing, and in gear while printing. Great strength is imparted to the frame, and the type bed is particularly rigid. These points, together with a truly turned and polished cylinder, with carefully planned means of adjustment, much simplify the preparation of making-ready of any kind of type-forme or blocks for printing, which is carried out much in the same way as on the ordinary single cylinder, but in a more convenient manner. Many of these machines are made to print four double crowns, 60 X 40 in., or even larger.

continuously rotate, the web of paper travelling in and out, in a serpentine manner, between various cylinders of two aharactersone (the type cylinders) carrying the surface to be impressed, usually curved stereotype plates, and the other (the impression cylinders) giving the desired impression. Such a press, if driven by electric power, is set in motion by merely pushing a button or small switch, a bell first giving warning of the press being about to move. The number of duplicate sets of stereotype plates to be worked from by these presses is determined by the size and number of the pages to be printed, and this in turn is regulated by the capacity of the machine.

As already explained, the forerunners of the rotary presses of the present day were the type-revolving printing-machines, and, whilst they were still being used, experiments were being made to cast curved stereotype plates which would facilitate and simplify the work of producing newspapers. This was successfully accomplished by the use of flexible paper matrices, from which metal plates could be cast in shaped moulds to any desired curve. These plates were then fixed on the beds of the Hoe type revolving machine, which were adapted to receive them instead of the movable typeformes previously used. This new method enabled the printers IIIC3'?ui:"'??N i i !4? ???;h l ' '? ? ? ? ? ?  1..? ? ? // ' >?/??pa??ji?g?fi??,?????'1a?1 1? ? W? I ? J ? C ? - ?r'? ' 0 ?? ?; 0Pn? - Vrar.r_?rr?r?elri  ,?? I FIG. 8. - Payne & Sons' Two-colour Single_ Cylinder_l/Iachine.

The two-colour machine is generally a single cylinder (fig..8) with one feed only, and the bed motion reciprocating. The two colours are printed each at one revolution from the two Two-Colour type-formesas they pass under the cylinder, which rotates twice in its travel. A double inking apparatus is of course necessary, and the inking arrangements are placed at the two extreme ends of the machine. In comparison with the ordinary single cylinder the two-colour machine is built with a longer frame, as is necessary to allow the two type-formes to pass under the cylinder, both in its travel forward and on its return. This cylinder on its return is stationary, in fact it might be called a double or rather an alternative stop-cylinder machine, with the inking facilities arranged somewhat on the same plan as on either a two-feeder or a perfecting machine. These two-colour presses are intended only for long runs, short runs may be worked to advantage separately on the ordinary single-colour machine. Generally, with the exception just mentioned, the machine is much the same as the ordinary stop or Wharfedale.

Before leaving the subject of printing with the reciprocating bedmotion, it may be mentioned that although in all modern machines of that kind the printed sheet is self-delivered, the imprinted paper has generally been fed in by hand, and for some classes of work this is still done. But many automatic feeders have been invented from time to time, which for the many purposes for which they are suitable must be reckoned part of a modern printing establishment.

As distinct from flat bed printing with a reciprocating motion, printing on rotary principles is a most interesting study, and it is Rotary this department of printing mechanics which has developed so very much in recent years. It seems almost as though this branch had reached its limit, and as though any further developments can only be a question of duplication of the existing facilities so as to print from a greater number of cylinders than, say, an octuple machine. This would be merely a matter of building a higher machine so as to take a larger number of reels arranged in decks. As the name implies, these presses are so constructed that both printing surfaces and paper to duplicate the type pages and to run several machines at the same time, thus producing copies with far greater rapidity. In some large offices as many as five machines were in constant use. About this period the English stamp duty on printed matter was repealed, and this materially aided the development of the newspaper press.

Subsequently the proprietors of The Times made various experiments with a view to making a rotary perfecting press, and as a result started the first one about 1868. It was somewhat similar in design to the Bullock press, so far as the printing apparatus was concerned, except that the cylinders were all of one size and placed one above the other. The sheets were severed after printing, brought up by tapes, and carried down to a sheet flyer, which moved backwards and forwards, and the sheets were alternately " flown " into the hands of two boys seated opposite each other on either side of the flyers. Hippolyte Marinoni (1823-1904), of Paris, also devised a machine on a somewhat similar principle, making the impression and type cylinders of one size and placing them one over the other. About 1870 an English rotary machine called the " Victory " was invented by Messrs Duncan & Wilson. It printed from the web, and had a folder attached. An improved form of this machine is still in use. This machine had separate fly-boards for the delivery of the sheets. In 1871 Messrs Hoe & Co. again turned their attention to the construction of a rotary perfecting press to print from the reel or continuous web of paper, and from stereotype plates fastened to the cylinder.

The rotary presses in use at the present time are indeed wonderful specimens of mechanical ingenuity, all the various operations of damping (when necessary), feeding, printing (both sides), cutting, folding, pasting, wrapping (when required) and counting being purely automatic. These machines are of various kinds, and are specially made to order so as to cope with the particular class of work in view. They may be built on the " deck " principle of two, three, four, or even more reels of paper, and either in single width (two pages wide), or double width (four pages wide). Single and two-reel machines are generally constructed on the " straight line " principle, i.e. arranged with the paper at one end of the machine, and passing through the cylinders to the folder at the other end where the copies are delivered. Threeand four-reel machines have also been constructed on the same principle, but the more usual arrangement of the four-reel press is to place two reels at either end, with the folders and delivery boards in the centre. This makes it possible to operate them as independent machines, or to run in combination with each other.

When presses are made in double width a two-reel machine is known as a quadruple, a three-reel as a sextuple, and a four-reel as an octuple machine. Double sextuple and double octuple machines are made, having six and eight reels respectively. The quadruple machine is a favourite one and is perhaps most in demand for newspaper work. This press prints from two reels of the double width. The first reel is placed to the right of the machine near the floor, and the second at the back of the machine and at right angles to it. A quadruple machine will produce 48,000 copies per hour of four, six or eight pages; and proportionately less of a greater number of pages; all folded, counted and pasted if required. The four cylinders, which are on the right-hand side of the press, are respectively the plates, four pages on each type cylinder, making a total of thirty-two pages in all. Each press produces of that number of pages 50,000 copies per hour, printed both sides, cut, folded and counted off in quires complete; by increasing the sets of Rotary  stereotype pages the same machine will produce 100,000 Machines.  copies per hour of sixteen pages, and by duplicating the folding and delivery apparatus, 200,000 copies of eight pages of the same size. This mammoth press measures 54 ft. in length, 19 ft. in height and 12 ft. across; its dead weight is about I io tons, and roughly Ioo,000 different pieces of metal were used in its construction. The rough cost of such a machine is probably about £18,000. Such a press requires two 55 h.p. motors, one at each end, to drive it. The press is practically four quadruple machines built together, each of which can be worked independently of the other. The paper is fed from reels placed at the two ends in decks, one above the other, each reel containing about five miles of paper, and weighing about fourteen hundredweight. The process of unwinding these long reels of paper in the course of printing takes only half an hour; they are arranged on a revolving stand so that directly they are FIG. 9. - Hoe's Double Octuple Rotary Machine.

printing and impression cylinders - the two inside ones being those giving the impression, and the two outer ones bearing the printing surfaces. The inking arrangements are placed at the two extreme ends of these four drums or cylinders, thus being near the type surfaces in each case. As the paper is unwound from the reel below it travels between the first two cylinders when it is printed on the first side; it then passes to the third and fourth cylinders, which give it the second backing side, thus " perfecting " the printed sheet. From this point the long sheet is carried overhead to the left-hand side of the machine, where it is cut longitudinally and divided, and then associated with the other web similarly printed by the other half of the press. They then descend into the two different folders, where they are folded and cut - the copies being discharged on to the delivery boards situated at the two sides of the left-hand portion of the machine, and each quire is counted or told off by being jogged forward. This description applies to one half of the machine only, for while this is in operation the same thing is being repeated;by the other half situated at the back.

Another machine, somewhat complex but quite complete in itself, is that constructed by Messrs Robert Hoe & Co. in London from drawings and patterns sent over from New York, for weekly papers of large circulation. Double sets of plates are placed on the main machine, which is capable of taking twenty-four pages, but by using narrower rolls the number of pages may be reduced to either sixteen or twenty if a smaller paper is desired. In addition to the body of the paper it prints a cover, and is capable of producing 24,000 complete copies per hour, folded, insetted, cut, pasted and covered. That portion of the machine which prints the cover is fed from a narrower reel of a different colour of paper from that used for the inside pages. The printing surface for one side of the cover is placed at one end of the cylinder and the reverse side is placed at the other end. This ingenious combination results in the printing of one cover for every copy of the paper.

The double octuple machines (fig. 9) erected by the same firm for the printing of Lloyd's Weekly News were probably, in 1908, the latest development in rotary printing. These presses print from eight different reels of the double width, four placed at each end ,of the machine, the delivery being in the centre, and from eight sets of spent the stand is turned half way round, and four other full reels already in position are presented ready to be run into the press. This ingenious arrangement, whereby the reels can be changed in about three minutes, obviates the loss of time previously incurred by the press being kept standing while the empty spindles were removed and replaced with four full reels.

Having described some representative types of the different classes of printing-presses in use, we may now treat of the methods employed by the workmen in securing The pre_  the best results in printing. The real art of printing, paration or  as far as presswork is concerned, lies in the careful Making-  preparation of the printing surface for printing before ready for era ling.  running off any number of impressions. This preparation is technically called " making-ready," and is an operation requiring much time and care, especially in the case of illustrated work, where artistic appreciation and skill on the part of the workman is of great assistance in obtaining satisfactory and delicate results. Theoretically, if both type and press were new, little or no preparation should be necessary, but practical experience proves that this need of preparation has not yet been entirely obviated and still remains an important factor. Single proofs of type, stereotype, electrotype or blocks of any description can often be struck off without making-ready with fairly good results, but if precision of " colour " (that is, inking) and uniformity of impression throughout a volume are desired, it is necessary to put the forme, whether type or blocks or both, into a proper condition before starting the printing of an edition, whatever its number. And this applies to all good work produced from whatever presses or machines other than those built on the rotary principle. In these, even if time permitted, little can be done in the way of making-ready; nor is it really necessary for newspapers, printed and read one day, and then generally thrown away the next. But for finely printed works this preparation is essential; the actual results vary with the operator, both as regards quality and, what is very important to the employer, in the length of time taken. Some men labour more at it than others, and it is considered that a press is only really paying while it is actually running.

The system of making-ready employed now is quite different from that in use when it was necessary to dampen paper before it could be satisfactorily printed. It was then customary to print with a good deal of packing, usually consisting of a thick blanket together with several thicknesses of paper, all of which intervened between the printing and the impression surface, whether the latter was flat or cylindrical. There was much in favour of this system, because a good firm impression could be obtained, and the " nutmeg-grater " effect on the reverse, when the impression was too heavy, could, after the sheets were dry, be removed by cold-pressing in a hydraulic press. It is still the best method for obtaining first-rate results in fine work, where hand-made or other rough paper is used. But the demand for cheap literature required quicker means of production, and the introduction of process blocks, especially those made by the half-tone process, necessitated the use of smooth paper and a faster drying ink, both of which are to be deplored, because to calender the paper to the degree requisite for this kind of printing practically means destroying its natural surface, and in rendering the ink quicker in drying the pigment undoubtedly suffers. On the other hand, there has been a compensating advantage in the fact that improved machinery has been demanded for this class of work, and the British manufacturer has been stimulated by the American manufacturers, who have taken the initiative in the change of methods in printing. Cylinders are now turned so truly and ground to such a nicety that very little packing is required between type and sheet to be impressed, so that a new system of making-ready, termed " hard-packing," has been resorted to. The fact that the iron impression cylinder was nearer the type forbade the large amount of soft-packing formerly used, besides which process blocks, whether line or half-tone, could not be rendered properly by a soft impression. Although less packing is necessary, greater care is required in preparing type or blocks for printing by this new method.

The method in making-ready ordinary plain formes is as follows. The type-forme is placed on the coffin or bed of the press and fixed into its proper position - the precise position being regulated by the exact size of the sheet of paper on which the work is to be printed. The cylinder is first dressed with a fine and thin calico drawn tightly over and fastened securely, which serves as a base on which to fasten sheets. A sheet of some hard paper, such as manila, is then placed over it to form, as it were, a foundation.

The printer next proceeds to pull a sheet, without ink, to test the impression. We take it that the machine has already been regulated by means of the impression screws at the respective ends of the cylinder for all-round or average work, and that any inequality of impression can be remedied by adding or taking away from the sheets on the cylinder. Now, supposing the forme to be dealt with consists of thirty-two pages to be printed on quad crown paper, measuring 40X30 in., on a suitable size of single cylinder machine of the Wharfedale class, it would be found, although both the machine and type were fairly new (that is, not much worn), that there was some amount of inequality in the impression given to the whole sheet. This is easily detected by examining the sheet the reversed side in a strong side-light. Although the greater part may be fairly even, some pages, or portions of pages, would show up too strongly, the impress almost cutting through the paper, while in other portions the impression would be so faint that it could hardly be seen. These differences of impression are called respectively " high " and " low." All these difficulties have to be rectified by the printer either overlaying or cutting away pieces in this first trial sheet. If the " set " of the cylinder is about correct, and the impression sheet has been taken with neither too many nor too few sheets on the cylinder, it will be a matter rather of overlaying, or " patching up," than of cutting away from this trial sheet. As soon as this first sheet has been levelled up it is fixed on to the cylinder to its exact position, so that it will register or correspond with the type when the press is running, and another trial sheet is struck off, which is treated precisely in the same manner, and is then fastened up on the cylinder on top of the first sheet. It may even be necessary for fine printing to repeat this a third time, especially if the forme includes blocks of any kind. When this preparation is completed, the whole is covered up by a somewhat stouter sheet, which forms a protection to the whole making-ready, but which can easily he lifted should it be necessary to give any finishing touches to it before beginning to run.

If the forme to be printed consists of both type and blocks mixed, a somewhat different treatment has to he employed in order to put the blocks into a relative position with the type for printing. This is done by the usual trial impression sheet, and, as blocks are found to vary much in height and are generally low as compared with type, this deficiency has to be remedied by underlaying the blocks so that they are brought to the height of the type, or a shade higher. This is usually done by pasting layers of thickish paper, or even thin cards, underneath the blocks. This must be carefully done so as to make them stand squarely and firmly on their Lase, in order that they may not rock and give a slur in printing. After underlaying, and to emphasize the respective degrees of light and shade in the illustrations, a separate and careful overlaying is required for the blocks before anything is done to the main forme. This is particularly necessary if the blocks are woodcuts, or electrotypes of woodcuts, which require a different cutting of perhaps three different thicknesses, all on thin hard paper, to give their full effect. But with half-tone process illustrations very little overlaying is required, provided the blocks have been brought up to the proper height by underlaying in the first instance - the various tones being already in the block itself - and it is little more than a matter of sharp, hard impression to give full effect to these, if both paper and ink are suitable. For line process blocks a still different treatment in making-ready is desirable, so as to get rid of the hard edges which are nearly always found in this kind of block. Here too it is essential that the preliminary underlaying be done with extreme care if good work is desired. The originals and the engraver's proofs are of great assistance to the workman in bringing out the details of an illustration when he is preparing it for printing. In rotary printing from the curved stereotype plate and from the endless web of paper much can be done to assist the printer if good stereotype plates are supplied to him, and, if the forme contains any illustrations, both the artist and the engraver can help him if they keep in mind the particular character of illustration which they are preparing for the press. The artist can accentuate the high lights or solids in the original drawing or photograph, and the stereotyper can emphasize points in the picture by thickening the plate in the parts necessary to stand out.

The past generation has seen many improvements in printing machinery, all tending to an increased production, and generally to the betterment of the work turned out. This is particularly true of three-colour printing (see Process), which for commercial purposes has been brought to a high degree of perfection. Only what may be fairly considered as representative presses have been dealt with in this article, but there are many others, some of which have been most ingeniously constructed for special purposes. Process engraving has practically superseded wood engraving, and the new processes have brought new conditions, requiring a different making-ready, paper and ink. Some of these altered conditions are to be regretted. For instance, it is unfortunate that the quality and surface of papers have to Le sacrificed to the demands for cheap literature, and this especially applies to illustrated work.

The introduction of the autoplate is of great advantage to those using rotary presses, because it allows the production of a large number of duplicate stereotype plates of satisfactory quality speedily. This is all important in a newspaper office, where the margin of time between the caseroom and machine department is usually so limited, for it permits several machines being quickly equipped with duplicate sets of the same pages.

Power is another matter that is changing fast. Electricity is supplanting both steam and gas, and is being installed in most large printing-houses, including newspaper offices. Suction gas is being tried in some offices as a supplanter of electricity and is said to be much cheaper as a power producer. The independent system of motors is generally adopted, because it is found more economical and better for driving purposes, besides dispensing with the overhead shafting and belting, always unsightly, and dangerous to the workpeople. Speeds can be regulated to a nicety for each separate machine, and any machine can be set in motion by pressing a button.

A printing-house of average size, which makes book printing a speciality, consists of many departments under the supreme control of a general manager. His deputy may be said to be the works manager, who is responsible for all work being produced in a proper manner by the different departments. The progress of the work is as follows. a Printing  The MS., or " copy " as it is called, is handed, with all e  instructions, to the overseer of the caseroom, who gives it out to the compositors in instalments as they finish the work already in hand. Formerly the greater bulk of composition was done on the piece-work system, but as machine composition has largely superseded hand labour for the more ordinary class of work, piece-work is declining, and there is a greater tendency to have the work done on " establishment " (" 'stab "), i.e. fixed weekly wages. When the copy is in type a proof is struck off and sent to the reading closet, where the corrector of the press (see Proof-Reading), with the aid of a reading-boy, will compare it with the original MS. or copy, and mark all errors on the proof, so that they may be amended by the compositor at his own cost before it is despatched to the author or customer, who in turn revises or corrects it for the general improvement of the work. The proof is then returned to the printer, and if these corrections are at all heavy, another proof, called the " revise," is submitted, together with the first marked one, so that the author may see that his emendations have been made. This may even be repeated, but when finally corrected the proof is marked " press " and is sent to the printer with the necessary instructions as to printing. After another reading or revision in the reading closet it is sent to the compositors, who make the final corrections in the type and hand the forme to the printing department to deal with. It is this department which contributes most to the success of any printing firm, and it requires a really good man at its head. He must be a thoroughly practical printer familiar with the different kinds of printing machinery. To make the department pay, the machines must be kept fully employed with the many classes of work that a large concern has to deal with; the wheels must be kept running as much as possible, and the time for making-ready curtailed as far as is consistent with the proper preparation of the forme. Here again it is most important that a sharp eye be kept on the materials used. Ink forms a large item in the total expenses of this department, besides which there are: oil for lubricating, turpentine and other solvents for cleaning, paper for proofs and making-ready, &c. When the work is printed it is handed to the warehousemen, who are responsible both for unprinted and printed paper. astly, the counting-house deals with all accounts, both departmen s' and customers'.

## BIBLIOGRAPHY

The following books and periodicals may be specially referred to: Books - J. Southward (and subsequently A. Powell), Practical Printing, a handbook of the art of typography (2 vols. 8vo, London, 1900); J. Southward, Modern Printing, a treatise on the principles and practice of typography, &c. (large 8vo, London, 1900); C. T. Jacobi, Printing, a practical treatise on the art of printing, &c. (8vo, 4th ed., London, 1908); W. J. Kelly, Presswork, a practical handbook for the use of pressmen and their apprentices (8vo, znd ed., Chicago, 1902); C. T. Jacobi, The Printer's Handbook of Trade Recipes, &c. (8vo, 3rd ed., London, 1905); F. J. F. Wilson and D. Grey, Modern Printing Machinery and Letterpress Printing (large 8vo, London, 1888); Robert Hoe, A Short History of the Printing Press (4to, New York, 1902); T. L. de Vinne, The Invention of Printing (New York, 1876). Periodicals - The British and Colonial Printer and Stationer (London, bi-weekly); The British Printer (Leicester, alternate months); The Printer's Register  (London, monthly); The Printing World (London, monthly); The Caxton Magazine (London, monthl y); The Printing Art (Cambridge, Mass., U.S.A., monthly) The Inland Printer (Chicago, monthly); The American Printer (New York, monthly); The International Printer (Philadelphia, monthly). See also the bibliography attached to the article TYPOGRAPHY. (C. T. J.)