U CEN T E/) £yc AS Metal Plate Printing A TREATISE ON Printing in the Lithographic Manner from Zinc and Aluminum Plates Compiled , Edited and Elucidated in the Office of The National Lithographer < offset press, it may be of interest to chronicle a good method of transferring from left to right. By laying a properly prepared metal plate directly upon the stone upon which an engraving or drawing has been made (of course having previously been charged with transfer ink) placing the usual backing sheets upon it, and pulling through the press with strong pressure, an impression wall be obtained thereon equal in every re- spect to the original. The counterpart of the original is now to be treated precisely the same as any other transfer made on metal plates ; that is to say, it should be gummed up lightly, dried, washed off with water and strengthened by rolling up. The completed trans- fer is only to serve as an original from which the regu- lar transfer impressions are to be made by the aid of the regular transfer paper to another plate, or stone. It will be observed that this method makes it pos- sible to squash an impression from one piece of paper to another, for the transferrer now has two plates to work from, if he is contemplating a “from left to right transfer” ; at any event he is working from an original, as near as the term can be applied. 89 90 Metal Plate Printing By the above process we understand a mode of transferring which is to complete, for instance, the right half of a drawing or engraving, of which the left half only was made, or perhaps one-quarter only was necessary to engrave, and all the rest was left for the transferrer to complete. It is possible to get. good re- sults from plates not processed, of course, but it is ad- visable to secure these plates from competent plate- makers, who know exactly what is needed in this work, and any kinking, or other troubles that often follow home-made plates, is obviated. In completing these “left to right transfers” the plate is taken from the stone and thoroughly cleansed, then rubbed down with pumice powder and a ball of paper, or a felt pad, and water; again rinsed, flowing in a citric acid solution, say 15-20 parts chemically pure citric acid (crystals) in 100 parts water. .Care must be taken to apply this so- lution evenly. After three minutes the plate may be rinsed again, taking chemically purified cotton to rub the plate dry, the object being to remove all traces of crystalline metal. A thoroughly dry cloth is finally used to complete the drying, and the plate must then show no stripes or spots, if a thoroughly serviceable original transfer is desired. Should it happen that the first effort did not re- sult in a successful original, the plate can be again used by removing the ink with turpentine and a rag, then using another rag with benzine, which will take out all the grease, finally using pumice powder; the plate is given a good polish with that, again rinsed, and pre- pared with the citric acid solution. Re-transferring 91 In the event that a plate has been standing a long time with a transfer upon it, it should be treated, after the turpentine and benzine application, with a flooding of hot soda in order to saponify the settled fat, which might have drawn into the plate. A great many ideas about the various methods of transferring have been set forth in this chapter, and while, as we have previously stated, there is no hard and fast rule — every transferrer having his own ideas about the way his work should be performed — there is enough material to interest the man who is seeking light on the way other people work. r Re-transferring from Type W HILE there has always been some demand for transfers from type in the lithographic estab- lishments of the country, the advent of the offset press has increased the use of such transfers very largely. Of course all type transfers have to be reversed for the offset press. The type page, from the first in- troduction of movable type, has been “negative.” To imprint direct on paper would, of course, be “positive.” The difficulty of re-transferring from the type form to the metal plate of the offset press has discouraged many good transferrers. Fortunately considerable progress has been made in this part of the business and many difficulties have been overcome. When the offset press was first introduced it was the prevailing custom to reverse the type forms in the same manner in which the old engravings were reversed — the paper to paper method. Of course a type press of some kind had to be used, as the pressure in type printing — except in the case of the cylinder press — is entirely dif- ferent from that used in stone printing. It is practically impossible to print a type form on a lithographic trans- fer press — the same thing applies to an attempt to print from stone on a type press. The one calls for a direct pressure and the other for a “scraping” or sliding motion. 92 Re-transferring from Type 93 As the average lithographic transferrer had little or no knowledge of type printing, and as the type printer had no knowledge of lithography it usually took two men to make a transfer from a type form to a printing plate. This condition still exists, for that matter, especially where fine work is to be transferred. In the “paper to paper” process it is best to have the page or form to be printed “made ready” on a type press by a type pressman. This should be done with ordinary type ink. See that every letter shows up plainly on the proof and that the cuts print clear and clean. Make the impression light, but not so light that there will be any- thing omitted. Now wash the type ink off carefully and thoroughly and ink up the rollers with transfer ink and pull an impression on dry transfer paper. Place this im- pression face down on a piece of damp transfer paper and run the two pieces through the transfer press with a firm pressure. The damp sheet will now show the form in the negative and ready to put down on the printing plate of the offset press. In the transferring of the positive image on the dry sheet of transfer paper to the. negative on the damp sheet there is always great danger of “squashing” it and spoiling the transfer. This danger is so great that many efforts have been made to do away with the process en- tirely. Probably the most successful method of making a re-transfer from type is known as the rubber blanket method. This is practically the same as that previously mentioned, with this exception : In the place of the dry piece of transfer paper upon which the type impression. is 94 Metal Plate Printing taken, a piece of rubber printing blanket is used. This is laid smoothly upon the tympan of the printing press and a light impression is made upon it with transfer ink. The regular offset blanket is best to use. This impres- sion, of course, appears in the positive. Now place the rubber blanket in the transfer press and lay a dampened piece of transfer paper on it face down. Pull it through and you have the negative transfer that is used to lay down on the printing plate of the offset press. This method has been found to be very successful and one enterprising transferrer has patented a machine for stretching and holding the rubber blanket taut while the impression is being taken. The machine is well worth all that is asked for it as it facilitates matters consider- ably. By this rubber blanket method a perfect transfer can be made nearly every time if a little care is taken. Still another method is known as the zinc plate process. This is done by substituting a soft, thin zinc plate for the rubber blanket, pulling an impression direct from the type on the plate and then taking the negative transfers from the plate for putting down on the print- ing plate of the offset press. One great advantage of this method is that the plates can be laid away and kept as originals in case the work should ever have to be duplicated. A transferrer is one of the most important ad- juncts to successful lithographing and the transferrer who can do the same thing in more ways than one is the man sought these days. As nearly every conceiv- able mode of transferring has been touched upon here there is no reason why the man who has never had any- The Mode of Printing 95 thing to do with metal plates ought not to familiarize himself with the latest plan of operation. If he is in- terested in his woriiand desires to keep up to the times a close study of the schemes here outlined will, we trust, be of value to him in promoting his ambition. Metal Plates and the Offset Press The Mode of Printing HE rubber blanket offset printing press, the latest product of the press maker’s ingenuity, has as its basis the substitution of metal plates for lithographic stones. Without metal plates the rubber blanket press would be impossible, and for that reason it is well to bear in mind the very important part that these plates play in modern lithography. The method of preparing metal plates for the various stages of printing have been fully set forth in other chapters. After the plates have been prepared and the work transferred and rolled up, as described elsewhere, and it is gummed up and allowed to dry, it is then ready, after washing out, for printing. The process of printing by the offset press is by no means a difficult one. In fact when it is carefully studied one is surprised at the simplicity of the whole affair. Three cylinders, one to carry the printing plate, another to carry the rubber blanket, and a third to carry the sheet and effect the impression from the rubber blanket to the paper, is all that is required. The fewer the additional parts, the better the press and the more easily it will be learned and understood. Of 96 Illustrations of Offset Presses Rutherford Offset Press Manufactured by FUCHS & I/ANG MANUFACTURING CO. New York City Sizes Made: 28 x 34 ; 28 x 42. Manufactured by THE HATE PRINTING PRESS COMPANY Dunellen, N. J. Hall Rotary Offset Press Sizes Made : 28 x 36 ; 35 x 48. Harris Automatic Offset Press Manufactured by THE HARRIS AUTOMATIC PRESS COMPANY Niles, Ohio Sizes Made: 14x17; 22 x 28; 24 x 34; 28 x 34. The Hoe Rotary Offset Press Manufactured by R . HOE & CO. New York City Sizes Made : 22 x 34 ; 28 x 40. Kellogg Rotary Offset Press Manufactured by ANDREW H. KEEEOGG CO. New York City Sizes Made: 34 x 38 ; 34 x 58 Manufactured by POTTER PRINTING PRESS COMPANY Plainfield, N. J. Potter Rotary Offset Press Sizes Made : 28 x 34 ; 30 x 42 : 34 x 44. Scott Rotary Offset Press Manufactured by WAI/TER SCOTT & COMPANY Plainfield, N. J. Sizes Made : 28 x 38 ; 32 x 46 ; 36 x 50. The Offset Press 109 course there are a certain number of gears, shafts, and rollers, etc., but primarily the press consists of three cylinders. There are several features of offset lithography that assure it permanency as a lasting feature of the trade. In the first place the rapidity of the work and the fact that the output of the press can be handled almost immediately after it is printed gives it a place in lithography that has heretofore been vacant. The fact that rough paper can be handled, and a clear, clean and sharp impression secured without the punching through that is bound to occur where type or plates are used or the omissions of parts of the work where stone is used, makes this process of the utmost value to lithographic establishments. When you take into consideration the fact that a metal plate takes the place and does the work of a stone costing many times as much, and all danger of breakage is eliminated, and the plate can be stored in a fraction of the space required by the stone, there can be no question as to why every- body in the trade ought to be interested in the metal plate question. When it is taken into consideration that the rough- est as well as the. hardest papers can now be made to take up the ink impression in perfect solidity and sharpness, and with the use of only about one-third the usual amount of ink on the work that would be necessary if printed direct from stone by the flatbed or direct rotary machines, then the vast importance of the offset method will be at once apparent. This power of securing a more solid and sharp impression with a 110 Metal Plate Printing less volume of ink preserves the work on the plate, as it does not have to be fed with an overplus of ink to fill in the pores of the paper during impression, as is the case when printing direct from the actual printing surface to paper, and, consequently, the trouble of filling-in, scumming, and thickening of the work is virtually pre- vented by removing the chief cause. This means longer runs without deterioration of the work, and less trouble for the machine man in applying solutions and antidotes to both ink and dampening water, to say nothing of the economy effected in the amount of ink consumed. As either zinc or aluminum plates are em- ployed as the printing surface, an additional economy is here effected over the use of stones. So elastic and adaptive is this rubber offset im- pression method that such uneven surfaced papers as imitation crocodile skin embossed papers are per- fectly printed upon, even with such work as fine copper- plate headings, and without destroying the indent markings of this peculiar paper — a feat unattainable by any other known process of printing. With such absorbent papers as common brown wrapping paper we have secured a perfectly flat and solid impression with the thinnest film of ink on the forms. There is absolutely no need for etching the work into high relief : in fact, this would be a drawback for this class of machine, as the rubber blanket would soon become in- dented and rendered uneven for succeeding work. The sheets receive much less pressure than they would do if printed direct by the old method, and as the rubber impresses the ink most delicately to the The Offset Press 111 paper — similar to the fleshy pad of the human finger — there is less stretching and distortion of the paper during printing, less risk of creasing and overlapping and so much better register can be obtained for color work on plain papers. But the merits of the offset machine are not alone confined to the improvements effected with the old form of work. For example, lithographers can now accomplish with photo-mechanical half-tone work what has hitherto baffled the typographers to attain, that is, they can print ordinary half-tone images on plain uncoated papers, free from the injurious gloss and glare of the highly glazed coated papers now in universal use for this work. Thin paper can be used as successfully as thicker paper, and thus both the weight and the bulk of the printed sheets will be most materially reduced. In printing half-tone work by the rubber litho- graphic principle, we get a pure solid dot impression, not, as with the typographic process, the raised point of the half-tone forced partially into the glazed paper surface, so that the center of the dot becomes denuded of its ink, as this has, during the act of impress, be- come squeezed out around the outer edge, in the form of a very obtruding penumbra. This drawback is eli- minated by the offset method and if use is made of the high light and sensitive process method, we have the most perfect half-tone printing methods extant. When the first steam or power press was introduced in this country about forty years ago, like most new in ventions, it was greeted with the utmost contempt and 112 Metal Plate Printing condemnation by the lithographers who failed to see any- thing good in the new order of things. However, the steam press has been used ever since and it was the making of the lithographic business in a commercial way. Then press manufacturers began to experiment with the steam press and from that came the metal rotary press. The French claim that as their invention, while an Ameri- can manufacturer avers he was the inventor — however, it came, and added improvements have given us the rubber-blanket offset press, which gives us the. premier position in modern lithography. With this offset it is possible to make a transfer on metal, in much less time than it takes to transfer to stone, put the plate on the press in less time, and instead of printing 1200 im- pressions an hour, or 7000 a day, several hundred estab- lishments are printing more than 5000 an hour and the work covers every phase of lithography. The progress in reaching the present stage of effi- ciency is very interesting. With the introduction of metal plates the wise printers were not content to work in the old way on flat-bed presses with their small out put and those engineers of an inventive turn of mind directed their attention to the construction of rotary machines on which the plates could be used. When it had been demonstrated that the rotary press was a thoroughly practical machine, the builders decided to go a step farther and try a press that would print two colors at one time — a two-color rotary. Never had it been commercially practical in lithography to print two colors from stone in one run through the old flat-bed press, although two-color flat-beds have been made. The Offset Press 113 Inventors, lithographers, and press builders have striven for years to perfect a machine which would allow them to put on the various colors of a picture in one run through a press. It was found that perfect register was obtainable in a rotary press, and from the form of con- struction of the machine it was possible to put in a third cylinder and an additional set of rollers, and put two colors on the sheet of white paper before it had passed through the press. Great as this improvement was in sur- face printing machinery, it was but a step to a three-color press, with the effects which are obtainable with the com- bination of three colors. Then still further improvements were made until now we have the rubber offset which can do multi-color work with startling rapidity and effec- tiveness. The rubber blanket, while not new in its application to printing, was formerly confined to tin printing, and its introduction to commercial lithographing dates back but a few years. It was found that an impression, be- cause of the elasticity of the blanket, could be had which would bring up every line in the engraving, no matter how fine it was. No matter how fast the press ran the work came out just the same. It was soon seen that the rubber blanket would print on a sheet of dry bond paper, as well as a stone press printed on a sheet of “super” or on a damp sheet of bond, and the very nature of the im- pression showed that if the ink rollers were working everything on the engraving must come out and come out clear. That settled the question of the practicability of the offset press for commercial work. It was agreed that a press that would turn out 5,000 sheets an hour and 114 Metal Plate Printing run along like a sewing machine, printing on dry bond paper, and bring out every line perfectly, had passed the experimental stage. Every sheet came out perfect and no accident of any kind occurred to stop the run. It was at this stage that it was generally agreed by lithographers who saw the offset in operation that it was adapted for commercial work. Since then the color work has been advanced to a state of satisfaction, if not en- tirely efficient, and each day greater progress in this phase of the machine is recorded. But to get right down to the way metal plates are handled after they have passed through the transferring process, which is the object of this dissertation: The several manufacturers of the offset press construct their machines differently, of course, but, as said before, they are in the main similar. There are three cylinders, al- though each machine possesses its variations and pecu- liar distinguishing features. The top cylinder in all of them is, however, the bed, or plate cylinder. Around this the metal plate is clamped for printing. The middle cylinder is the rubber or offset cylinder, while the bottom one is the regular tympan or printing cylinder. The inking arrangements for the printing plate are not unlike those on a web press, but the inking rollers provide a greater distributon than on any other machine made. In connection with the plate cylinder is a water fountain and a set of water rollers made especially for the offset press. The water rollers are locked down upon the plate cylinder before the inking rollers, and the machine is ready for business. The whole surface of the plate is damped except the transfer parts or the substances to be The Offset Press 115 printed, and of course the water does not act upon the greasy parts in any way: Now the ink rollers, passing over the plate will deposit no ink where the plate is damped, but they ink the transfers to the required strength. The inked up transfers print on the rubber cylinder, the sheets fed into the tympan cylinder receive their impressions from the rubber blanket and the work is done. The metal plates used are as thin as fine paper and the cut-off on the plate cylinders is only about one-sixth as deep as the cut-off on most of the flat-bed cylinders. When you look for the bearers on the offset press you have to feel for them. Anything like so shallow a cylin- der on the old-fashioned press would wear out the print- ing material in no time. It is right here, if nowhere else, that the offset press has achieved a triumph which will afford press manufacturers something to think about for some time to come. It has greatly reduced the terror of that awful word “wear.” The plates used are granted lasting qualities for the reason that the. pressure exerted upon them is very slight. It prints upon a rubber blanket of five-ply thickness, which is somewhat thicker than a rubber boot-leg. A man can press his thumb upon it and make a deeper indentation than takes place at each im- pression. This relieves the mechanism of all strain, and leaves the cylinders free to travel in absolute unison, which has heretofore been impossible. It makes no diff- erence to the offset whether it is turning out a heavy printing or a light one, the resistance in one case is not materially different from the other. Rigidity of con- struction, it may be said, has been placed almost second- 116 Metal Plate Printing ary to accuracy of contour, and in this last the builders have reached a degree of perfection never before realized. The variation in the printing surfaces of the cylinders are so slight that, were it mentioned by the fractional part of an inch, the expression of the fraction would con- sume a whole line in this book. An offset press does not have the appearance of running at such terrific speed when you stand alongside it, but when you get in front of one you see the sheets falling like so much confetti on election night. The ab- sence of static electricity in the paper is remarkable and proves that it has always before been the result of fric- tion. The sheets are gathered on a skeleton cylinder and delivered three at a time, or else they shoot out one after another in the manner that grain comes from a thrashing machine. Some times wonder is expressed that so thin a plate can be locked on the cylinder. The plate is made in various sizes to fit and instead of catches being used to clamp them on they are clamped into the openings in the cylinder. Offset presses will not consume much ink, and there- fore the quality must be there. If too much ink is used it makes trouble, but the ink makers are up to the times and are making the best ink of their lives; the pigment must be put into it, and less oil, etc. The metal plate — about which this work has been written — is the chief adjunct to this new press. Out in Cleveland an establishment is turning out sheets printed in eight colors on a 34 by 44 offset press, and beats anything so far seen in the color line. The The Offset Press 117 best of inks were used, of course, and the metal plates were prepared; while it is an every-day occurrence to see the offset — one kind or another — turning out four- color work, and presses in other establishments are doing the same thing in all parts of the country. In Europe members of the lithographic craft regard the offset press with suspicion, and only recently British lithographers reluctantly conceded that they were adapt- able for commercial work, such as invoices, memorandum forms, billheads, letterheads, policy forms and labels, pos- sibly in two colors, and such like work, but a job of high- class chromo postcards, done in no less than fifteen colors, from a German offset press has literally startled them. It affords some indication of the rapid developments that are taking place when we record that the basic process used for these postcards was a photographic original on a metal plate. The finished chromos are most pleasing, tasteful productions, and were printed from the offset machines at a higher rate of speed than this class of work was ever done before. With the general principle of the offset press fully recorded it will no doubt be interesting to show some- thing about the peculiarities of the several makes of this new process. As previously stated each make has its own little wrinkle and characteristics, and we shall en- deavor to point them out without fear or favor for the benefit of those interested in the subject. The Offset Process YEAR or so ago The National Lithographer made the assertion that the offset press would revolu- tionize the lithographic trade and it was scoffed at by many old lithographers who contended that while it might be possible to do some kinds of commercial work by the rubber offset process, the idea of doing color work on an offset press was the height of folly and the ravings of one unfamiliar with the subject. It was pointed out that as the work had to be trans- ferred to a metal plate and printed first on the rubber blanket and then to the paper, it was obviously impossible to do color- work on such a press. In the first place you could not carry color enough, then the register could never be made close enough for a color job, and then- well, all kinds of arguments were offered, and some of them sounded quite feasible, but finally first one press and then another got a trial at color work. One man put a color job on his offset press because he had no other press on which to work it— and he had to do the job. He was surprised at the quality of the work — as, also, were the other people who tried to do color work from their rubber blankets, but the work went right along and some very creditable jobs were turned out. But the scoffers said that coated paper could never be worked on a rubber blanket press. Of course every lithographer knows that coated paper is an “effect” rather 118 The Offset Process 119 than a “cause." People use it for certain kinds of work because they cannot print the work on paper unless it is coated. With the offset press it is not necessary to have coated paper in order to get the right effect — the offset printing attends to that— but some people insisted on coated paper and the offset press seemed to take to that just as it took to everything else that was offered to it. But the scoffers “stood pat” on the half-tone. There was a condition under which the new process must fall down. No offset press could possibly carry ink enough to enable it to print a solid half tone — that much was sure. The owner of an offset press put a half-tone down on a plate and started up the press. While it was a slow job to start the first time, the press not only printed it perfectly, but actually printed it on rough paper that the type press could not have worked to have saved the country from going to the dogs. The scoffers still maintained — and probably always will — that the offset process is not suited to any other kind of lithography than the commonest kind of commercial work, but in spite of that the differ- ent makes of presses are grinding away on almost any kind of work and getting away with it, while the scoffers, like a small coterie of Civil War veterans who refuse to admit that the war is even now over, still “stand pat.” Those who have used the offset press have found that the cheapest material from which lithographing or printing can be done successfully is the metal plate. A plate of this kind large enough for the biggest press costs less than five dollars, already to receive the transfers. Plates can be put aside and kept for years and then put on the press and run again. In the meantime they can 120 Metal Plate Printing be placed on a shelf or in any dry, clean closet without deteriorating. For magazine printing this new process offers a money saving proposition that cannot well be allowed to pass by the publisher. In the first place the process ad- mits of doing fine magazine work on paper of about one- half the thickness and weight of that now universally in use on work of that kind, and at the same time gives the reader just as fine looking work, .and the advertiser all that he could conscientiously ask for. A net saving in paper of fifty per cent, and the same in postage is as- sured. When the plates are to be preserved, as is the case with most publishers, the metal plate offers advan- tages that the electrotype never possessed. It takes up but a fraction of the space called for by the expensive electrotypes and will require practically no preliminary work in getting it ready for the press when a new edi- tion is wanted as the form is already made up and ready to run. The question of printing color lithography on an off- set press has been before the lithographic public for some time — in fact, ever since the introduction of the offset process. There are now on the market seven different makes of the offset press and nearly all of them are capa- ble of doing good color work. Some of them are printing in eight colors on sheets 29x43, and there are no heavy ones or light ones among them — the sheets are uniform. Indeed, some of the samples were printed from en- gravings made on stone for a stone press, and, although it is the generally accepted theory that work made direct comes out clearer than the reversed output, seems to have The Offset Process 121 made no difference. It is a fact known to those familiar with the offset press, that old, worn engravings can be made to show better work on the offset press than upon any other press on the market. While it is true the offset press was intended pri- marily for commercial work, it has gradually been work- ing its way into the color field and it has made good from the start. Some of the jobs of color work on exhibition in the office of The National Lithographer, made by the offset process, would be a credit to any process of repro- duction extant, and demonstrate beyond any possible doubt that in the field of fine color work, the offset press is to be a contender in the future. One of the latest offset presses is one that prints both sides of the paper satisfactorily. There are two large cylinders, divided in two distinct halves, each half of one cylinder carrying the plates for “first printing” and “reiteration” — eight pages of music on each half- cylinder. The other large cylinder is divided in half to correspond with the plate cylinder, and on each section is fixed a three-ply rubber blanket. Each revolution of the large inked printing plate cylinder transfers the music pages on to the rubber sheets on the second large cylin- der. Immediately above the rubber blanket cylinder is an impression cylinder half the size of the larger ones and also covered with a rubber blanket. This small rub- ber cylinder receives the inked up impressions from one half section of the large rubber covered cylinder and presses it against the sheet to be printed in due order for perfecting, and, in its revolution, presses the other side of the sheet against the impression on the other half of the large cylinder, thus printing both sides at once. The 122 Metal Plate Printing sheet picks up the inked impression from the rubber sharply, clearly and cleanly, without the slightest defect of any kind, the finest line work is as clean and solid as the heavy colors, and the register is said to be perfect. This machine, an English invention, can be used for printing two separate impressions on one side of a sheet. This is accomplished by turning over the gear connec- tion to a different position, and is done easily and with but small loss of time. The damping and taking-off ar- rangements are entirely automatic and easily regulated. To test the delicacy of impression of the new machine, some very coarse hand-made surface-ribbed deckle-edge paper was provided and run through to demonstrate that even this almost impossible paper for lithographic print- ing could be made to receive a good impression, a test which is said to have elicited the unstinted approval of those who witnessed the exhibition. Every day somebody discovers something new about the machine and the process that nobody dreamed of or believed a short time ago. Work has been produced on it that practically demonstrates that anything that can be lithographed at all can be done on an offset press. While one man makes a specialty of half-tone and type work, having acquired the knack of doing this kind of work a little better than anyone else can do it, another man dis- covers that maps and work of that kind can be done to better advantage on an offset press than in any other manner. Some people, on the other hand, have installed offset presses with the idea that once installed all that is necessary is to throw the copy at the press and the rest will be done automatically. This is a great mistake, for, while the offset press is undoubtedly revolutionizing the The Offset Process 123 lithographic trade, it requires skill and attention to make it work successfully. The many beautiful samples of lith- ography turned out by the offset press demonstrate clearly what can be done on it and, despite the skeptical, the more we see of the product of the offset press, the more thoroughly we are convinced that it is the process of the future. All that is necessary is proper material to work with, a little experience and good, hard common sense, and it can be made to turn out beautiful sheets of a regu- lar job. Metal Plate Press Work L ITHOGRAPHIC machine printing presents many peculiar features, each one of which requires care- ful and constant attention for their successful operation. The pressroom being the most important department in the lithographic establishment, it becomes imperative that the presses are made to run to their utmost capacity, whether they be the flat-beds or the rotary machines. A small amount of dirt will make more trouble for a press- man who is printing from metal plates than any one thing that he comes in contact with. This matter of cleanliness extends to the back of the plate that is to be used as well as the surface. It is, therefore, necessary to see that the back of the plate is thoroughly clean before the plate is clamped on the press. It should be wiped off carefully, 124 Metal Plate Printing and the cylinder as well, to prevent particles of dust and sand from lying between the bed and the plate. Another important thing to re ember is to have good grained rollers when printing on a rotary press. Rubber rollers are sometimes worked with success, but a leather roller is the best that has been made for the pur- pose. They require a great deal of care to keep them in good condition, and should always be kept soft, but not greasy. In running a metal plate it should always be gummed when stopped , and not left standing under the ink rollers, as there is always a little moisture in the roll- ers which will sometimes injure the plate, which has a tendency to absorb water. It is best therefore, to always sponge off the plate before starting up the press. Should a plate have a tendency to scum, a weak solution of neu- tralized nitric acid or a small quantity of gallic or tannic acid with a little gum added to the water in the water fountain will prevent it. There are preparations for ac- complishing this purpose manufactured by the makers of the processed plates, and where prepared plates are used it is best to purchase such solutions from them. When the metal plates are being set and started per- haps the best advice to give the machinist is to be syste- matic in his working. The morning's start should begin with the oil can. Go over the machine and its working parts yourself. Do not trust an inexperienced boy to at- tend to this important part of the day’s routine. See that oil-holes are clear, and lubricate most of those parts of the machine that have the greatest wear. Carry a rag or piece of waste in one hand to mop up any oil that may overflow, and to clean away any dust or dirty oil that may have accumulated. Metal Plate Presswork 125 Examine the ink rollers next, and if any of the skins are loose or baggy, have them rectified at once, and also see that the dampers are in good condition. When using the ordinary press, the carriage bed should be periodically examined and cleaned. If a stone is used as a support to the metal plate it might be well to use a piece of elastic bedding underneath it to lessen the risk of stone, breakage. When choosing this material it is well to see that the waterproof quality is obtained, any other sort being a source of danger owing to its uneven swelling with the application of moisture. Assuming that all these preliminaries have been car- ried through, and that the stone or iron bed support for the plate is at hand. Proceed to set as usual, using the spirit level first, and then, after lowering the stone, turn the cylinder over and raise the carriage evenly until the stone is firmly pressed against the cylinaer. Do not screw too tightly, but allow a little for the thickness of the plate that has to be placed upon it. The plate should be ruled along the front edge with a pencil to mark the exact margin to lap over the edge of the stone. The plate can now be inserted between the front locking-up blocks and the gripper edge of the stone. This is accomplished when the carriage of the machine is extended. When fixed in the exact position, bend over the stone, place a sheet of paper on the face of the plate and turn the cylinder slowly until it reaches the back edge of the stone. The plate by this means is flattened upon the surface, and is held securely while the back edge is. bent over the edge of the stone. 126 Metal Plate Printing The impression cylinder can then be released and the plate locked up in position by pressing the blocks against the sides of the stone. If the plate, after locking up, ap- pears to be a little slack, insert a long strip of wood be- tween the bent edges of the plate and stone. Lock up tightly against this and it will become perfectly flat and taut. When using a cast-iron bed as a support for the plate, level it up in the same manner as you do a stone. Bend the two edges of the metal plate to correspond with the width of the surface of the bed. Clean well the back of the plate and the top of the bed. Insert the plate at the gripper edge of the bed and lock up with the middle and end screws. Then repeat the operation on the back edge and tighten all the nuts. Run a few waste sheets through without removing the gum coating and without the use of dampers and inkers. This will cause the plate to stretch a little and settle to its proper level. The bars at the back edge of bed are then tightened to take up the slight stretch, and the bed can be locked up and the regis- ter obtained in the usual way. Supposing that the machine is now in readiness for printing, spread a little ink on the rollers and let it dis- tribute well before allowing it to touch the plate. The start should be made with a spare supply of ink rather than too much, until the correct quantity is reached. If the plate has to be printed from in black, the design can be washed out as before described and rolled up with the hand roller. Or if the job is in color, gum the plate up thinly, wash out with a clean dry rag until all traces Metal Plate Presswork 127 of the old ink are removed, apply a little grease or asphal- turn, add a little water and wash clean. The machine roll- ers can now be dropped and the plate rolled up in color. When making a start and obtaining register, etc., do not run the same sheets through more than two or three times, less if possible, as this is a frequent cause of work thickening owing to the amount of ink on the sheets be- ing continually pressed upon the clean parts of the plate. It also causes trouble by transferring some of the ink to the cylinder brush, which afterwards marks the clean paper as it goes through the machine. Do not fad to gum up and dry the plate if the ma- chine is stopped at any time. The careful observation of this rule will keep the plate in excellent condition and re- move one of the sources that cause the work to thicken up. If, when printing, the plate commences to tint or scum, the machine should be immediately stopped, the plate rolled up in black, chalked and etched. Then add a little magnesia to the ink or a few drops of tannic acid to the damping water. A little caustic soda solution applied to the edges oc- casionally will keep them clean and prevent the ink from catching. The foregoing advice on machine printing will give the beginner the chief lines of treatment necessary in set- ting and starting plate work. If the instructions contained therein are carefully followed, there is no reason why the pressman should not produce, at the initial attempt, work in every way equal to his best productions from the litho-stone. 128 Metal Plate Printing Of all the parts of the press which have an influence on the register, the grippers play the most important part, no matter what kind of a machine is in use. When these parts are not in order, that is to say, when they do not hold the sheets equally fast in all parts, exact regis- ter is not possible. Naturally the difficulty is less with small sheets; with larger sheets the grippers come into play more often, and consequently there is more likeli- hood that an equal number do not come into operation, one or the other of the grippers not holding the sheet so fast as the others. These differences appear still more when the grippers through striking, have become bent. They should never be hammered, as is often resorted to, though if it is done it should be done only by the most expert manipulator. Equally with the grippers the feed guide should receive attention. Where it is not smooth, or where the edges stand up too high, the sheet is pressed downward, or with paper which is wavy so that it does not lie smooth, the grippers cannot get a good hold without pushing the sheet away. This is a most important point in the effectiveness of the feed guide. Of the many annoyances associated with the machine printer’s task, grit is probably the most troublesome, in- asmuch as its presence is almost imperceptible, while its effect is extensive and often disastrous. Its sharp grains become embedded in the inking-roller skins, and plough tiny furrors across the printing forms, doing much dam- age before the printer realizes the presence of any for- eign matter on the inking-rollers. Dust the rollers and examine them carefully before commencing operations, and in this way ensure perfect cleanliness at the start. Metal Plate Presswork 129 This may seem a trifle, but trifles make perfection, and perfection is no trifle, some wise man said, and by ad- hering strictly to the rules of care and cleanliness in the handling of metal plates there should be no trouble with grit or other like substances. In conclusion the publisher of this book again urges the younger element in the lithographic trade to learn the business from the ground up, not forgetting that litho- graphy, although more than a hundred years old, is in its infancy right now, and is only beginning to take its place in the commercial world. More progress has been made in the past few years than actually took place in the pre- vious century, ignorance and prejudice, to say nothing of the foolish secrecy that prevailed, keeping this beautiful art confined to a narrow sphere. The young man in the trade faces a bright future, if he will devote his time and energies to mastering every detail of the work in hand, and keep abreast of the times. The older men, or at least some of them, will argue forever more that nothing can ever take the place of the lithographic stone, but they are wrong, sadly wrong, for the metal plate process of litho- graphic printing has demonstrated beyond peradventure of a doubt that it is a permanency. Photo-Lithography Its Growing Importance T HE wonderful strides that have been made in Photo- Lithography are no less remarkable than the ad- vance recorded in metal plate printing and the wonderful achievements accomplished by the offset press. This has resulted from a series of experiments which has brought Photo-Lithography, with its many branches and its ex- tended application, to a point where it is useful for the graphic arts, not only from a practical standpoint, but in the artistic sense as well. Like the metal plate and the offset press, its use has been restricted by prejudice and custom, but in the near future it will be a great acquisi- tion to the lithographing trade when it is once generally recognized that it is possible by that process to prepare a plate or stone by the aid of photography from any origi- nal. It matters not whether it be a drawing, a print, or an oil painting — larger or smaller than the original can be reproduced in the lithographic press. Photo-Lithography, in fact, has developed so rapidly of late that it is almost inconceivable to comprehend its possibilities. A new enterprise, having as its basis this process, recently began reproducing oil paintings by means of the lithographic press and the success has 130 Photo-Lithograp hy 131 created something of a sensation in lithographic circles. This new process makes its headquarters in Chicago, and, while the company working it proposes to enter the ad- vertising field, oil paintings were recently produced on canvass with such fidelity that the work could not be distinguished, a few feet distant, from the original paint- ing. Notable examples of oil painting reproductions are a painting of Sir Wilfred Laurier and one of President Taft. They are both mounted in heavy gold frames, and are attracting attention from the public generally, and lithographers in particular. Photography was not discovered by any one person, but was evolved by many minds. Through the revela- tion of Mungo Pouton, in 1839, that chromic acid is ex- tremely sensitive to light; through the disclosure that chromic gelatine becomes insoluble in warm water, by Talbot, and, finally, by the adaption of these principles to pigment, carbon and photo-lithography by Poitevin, a new field was opened up to graphic endeavor; the screen process being its highest realization on the printing press, and fully incorporated in lithographic methods today. The unexcelled principle of the litho-transfer, the ex- treme fineness of the Ben Day film, the introduction of metal plates, self-feeding machinery, the rubber blanket offset, rapid printing presses; in short, the host of me- chanical and chemical devices open to lithography, form a constantly growing galaxy adding new triumphs to the art. Lithography, it can be truly said, is mistress of all processes, because it is the method par-excellence, of the combined mechano-chemical processes, finding its fullest. 132 Metal Plate Printing most far reaching and economical exemplification in its versatile methods as practiced today. Through the advent of photography and the immense flood of light which it shed upon the reproduction and development of art, lithography was at once projected as the one method capable to participate most prominently with, and maintain her dignity toward all ; for instead of losing prestige, lithography blossomed out in new array, in rich colors, and at present stands unexcelled as the queen of chromatic reproductive methods ; artistically po- tent and commercially capable, she is the central figure upon the grand dome spanning the glorious structure of the graphic arts today. Imitation of the marvelous color displays of nature by the camera is the goal of photo-lithographers, and the camera now has the same power as the human eye — it can not only see, but it can reproduce color — and through it the lithographic trade will multiply its productions and extend its importance as an educator of the masses. Soon it may not depend upon the translation of brush and pal- ette to gather the secrets from the garden of Mother Nature. Upon this little globe of ours, floating in infinite space, the lithographic employer, as well as the litho- graphic employee, has become really an intellectual be- ing, constantly setting before the. public gaze the highest examples of art and striving to teach ideal color-culture as rendered in the grand displays of nature. The progress of chromatics will not cease. It has been planted in the human soul and is essentially for the advancement and progress of coming ages. The litho- graphic art is emerging from the confusion of mingled Photo-Lithography 133 colors, when registering marks were pulled apart, plates began to tint, streaks began to appear, and even solids walked right off the surface, and the progress being made, cannot be checked by the little men of the planet who al- ways oppose things new and novel. One of the most successful and beautiful photo- litho processes before the public at present, is that adopted by Frey, of Zurich. In this process the work is done entirely with zinc. The sketch, or other object to be reproduced is photographed through color films onto a plate coated with an asphaltum film. In the develop- ment, minute particles of asphaltum wash away, and leave the tones of the picture broken up with an exceed- ingly fine, irregular grain. These are three color photo- graphs taken and from these three are produced the number of colors necessary for working the design. The various color strengths are gotten by under and over developing. For instance, a pink or flesh tint would be obtained by under developing a print from a red nega- tive, supplemented by a fair amount of work put on by the litho. artist, such as filing in solids and taking away the high lights. The impressions from this process are very fine, and, as works of art, bring good prices. The question is often asked by many lithographers: Has not the camera in lithography driven out the artists element in the trade? In answer we say most emphati- cally, No. The chromo-optical process of making pictures has been nothing but a valuable acquisition to commercial lithography and has hurt no one. We need only to com- pare the results produced by that class of lithography twenty years ago, with that turned out today, and we will 134 Metal Plate Printing find where fifteen colors were used then, seven or less ’are used now, with the same effect. Naturally, in order to obtain this economic advantage the technical part of the. work had to advance 50 per cent ; so we find at pres- ent the work must be finer and closer, the textures must be more marked and diverse, the work more accurate, and at the same time it must be truer to nature. Photo- graphy and process have forced the lithographer to ad- vance likewise in his Ben Day, crayon or stippel work. So that instead of shedding a baneful influence upon the lithographic art, it has certainly benefited every one even remotely connected with the lithographic trade. It has educated the mind and eye of artist and public, as well as accelerated the dexterity of the lithographer’s hand — in other words, the graphic arts would have retrograded if it had not been for photography. For practical purposes the photo-litho. process may be classified according to the two chief methods : 1. The first, in which the plate or stone is coated with the light sensitive photographic substance and exposed under a reversed negative, so that a reversed image is formed on the stone or plate which, in printing, comes in the right position. 2. The other, in which paper or a very thin zinc plate, provided with a light sensitive film, is exposed un- der an ordinary — that is, not reversed — negative, and thus is rendered capable of receiving fatty ink and is then transferred to the plate or stone by transfers. The basis for the photo-litho. is generally a photo- graphic negative on glass or a gelatinous substance which, as the word negative implies, when examined by Photo-Lithography 135 transmitted light, must have all its tones reversed. That is to say, to be specific, the drawing, lines, strokes or points, which are to be black in the print, must look transparent, while the other part of the negative which forms the groundwork must be covered or opaque. Of the many processes, Fritz, the Vienese authority says, though differing in detail, they may all be assigned to one of the above-mentioned principles. However that may be, there are two which have been especially tested in practice, namely, for the direct transfer, as we will call it, that process which is based on the light sen- sitiveness of asphalt or of an organic substance in combi- nation with a chromium salt; and for the indirect trans- fer that process which is founded on the light sensitive chromium salt in combination with gelatine, or briefly on the light sensitiveness of chromated gelatine. All other more or less complicated methods have disappeared from technical practice and have now only the honor of being scientifically and theoretically correct, but for various reasons are not practically valuable. Until quite recently the direct process in its appli- cation to the lithographic stone or plate was uncertain in its results. It was impossible to secure sufficiently close contact between the negative and the stone or plate, particularly when large surfaces were under operation, and consequently the prints were seldom a complete suc- cess. But the successful application of the direct pro- cess to modern zinc and aluminum plates is now an ac- complished fact. The metal plate is sufficiently elastic to adapt itself to any inequalities on the surface of the nega- tive. Under such conditions as these this process offers 136 Metal Plate Printing at least one very important advantage — there is not the slightest possibility of distortion such as might occur in the development of the transfer. The methods used by some experimentalists for di- rect transfers, which began by coating the stone with a solution of gelatine, albumen, or gum made light sen- sitive with a chromium salt, and after exposure under a positive or negative, obtaining a printing plate, were com- plicated and troublesome, but the results were fairly safe and they are now more and more used in practice. Photo-Lithography in lines is simply the reproduction of line drawings or prints in which the design is repre- sented in black and white with such gradations that may be suggested by lines or dots. Half-tone Photo-Lithog- raphy is the reproduction of a design or copy which has in its composition gradation of tone in the form of flat tints. This is sometimes described as the translation of the graduated light and shade of the original copy into a surface which can be printed from by mechanical means for which purpose the ink bearing surface is broken up into the most minute sections, thus forming an almost imperceptible grain. The first attempt to reproduce the half-tone of a copy, in the form of a grain consisting of minute dots, were made with a screen of open textile fabric. This was done by placing the screen between the lens and sensitive plate but the results were, crude and unsatisfactory. It had the effect, however, of stimulating interest, and the invention of cross-line screens soon fol- lowed. In this latter method lines were cut on glass and filled with suitable coloring matter and it was at once recognized as a decided advancement in half-tone photo Photo-Lithography 137 process. The screen effect, is even now a drawback to its more extensive adoption, as fine etching cannot be re- sorted to as in photo engraving. There are no insur- mountable obstacles, however, to hinder the production of excellent transfers as this effect has to some extent been overcome by the use of a four-line screen in lieu of the usually crossed screen, while more recently a higher degree of excellence in photo process work has been at- tained by the adoption of a natural grain, which is un- doubtedly based upon Calotype methods in which reticu- lated grain is produced more or less suitable for litho- graphic prin f ing. Unlike the mechanical screen grain, the texture of this process reproduces the original copy with but little, if any, loss of expressive power. There is still much to achieve in photo lithography, and it is probably more owing to a full recognition of this fact that the progressive character of the process is maintained. Its commercial value is undoubted, and its successful application is chiefly a question of how and where it can be most effectively introduced. A photo print can now be made direct on either zinc or aluminum plates and by a slight modification of the photo engraving process can be developed according to lithographic methods. In a direct photo print on metal, the finer qualities of the work are much more likely to be retained than when a transfer print is made under the negative and afterwards transferred in the usual man- ner. One authority says, in discussing photo-lithography as applied to metal plates, that the plate should be finely grained and then coated with sensitized asphalt solution 138 Metal Plate Printing and exposed under a negative, for about five minutes in direct sunlight and about twelve minutes in a diffused light. The action of light on the asphalt solution is to render it insoluble in turpentine, so that if a sufficiently exposed plate is immersed in pure turpentine the lines, etc., of the design, being of course represented by clear lines in the negative, will remain intact, while the sur- rounding portions will be dissolved and washed away. After development, wash the plate freely in water, and dry it by fanning or using a pair of bellows. Let it stand for about ten minutes and then slightly etch it with a very weak solution of nitric acid. Cover the work with strong fresh gum and dry it thoroughly and quickly. Re- move the gum and rub up the design with black ink in the usual way, wash dry and dust over with French chalk. Every maker of metal plates supplies this special etching solution prepared for a certain quality and character of metal. After using the etching solution and gumming up the plate should be washed out with a dry flannel till all the work is removed. Sprinkle a few drops of water on the plate with a “rubbing up” rag and with a little ink and turps rub up the work till it is gently charged with ink, then roll up till the work or transfer looks strong and sharp, when the plate is ready for printing. Pen and ink sketches and wash drawings are entirely under the control of the artist and characteristic effects are chiefly due to bold and vigorous conception and skill- ful drawing. Scraper boards offer most remarkable pos- sibilities for black and white half-tone sketches. This consists of a light wood pulp board with a convenient Photo-Lithography 139 base upon which a thick coating of white composition is laid. Black ruled lines are printed on this surface and lines of similar texture are embossed at right angles to them. Drawings in pen and ink may be effectively han- dled by free and skillful use of the scraper. Embossed lines only are the peculiar features of these boards but variety of texture can be obtained by scraping these lines into dots. According to the existing technique of photo-litho- graphy and the almost perfect state of the transfer pro- cess, anything can be reproduced by this method. It rests in all its branches of application on so simple a principle, that any lithographic printer with a little practice and ob- servation, can attain absolutely good results. Before the discovery of the method of breaking up half-tones into points or dots, only line drawings could be re-produced by photo-lithography. Since it has been possible to break up half-tones nothing stands in the way of reproducing by this method any kind of original. The negative for photo-lithographic work must be- fore all things possess two principal qualities; when looked through it should be as clear and as clean as pos- sible, on the other hand the ground as well covered as possible. The deposit should be of a black color ; from a well drawn original, absolutely satisfactory negatives can be prepared without the black color. When a drawing is reduced which contains grey lines, dots, and points, as well as full black ones, toned lines will be visible as well as the transparent ; with careful treatment, the nega- tive may be so far corrected that it may be used. If this is not effected, or is not possible, the retouching may be somewhat troublesome. 140 Metal Plate Printing It will not perhaps be out of place to give here ac- counts of photo-lithographic methods that have recently been adopted by some of the leading printers who are at present turning out beautiful work by means of the camera and metal plates. Their method for obtaining in- taglio plates is processed by first etching the original print into slight relief and then reversing it. Another process, which is similar to the latest half-tone processes, is based upon the use of an asphalt solution to give the necessary grain. The sensitizing solution most generally used for metal photo-lithographing is prepared as follows: Take water, 1,000 parts; bichromate of ammonia, 3 parts; albu- men of eggs, 100 parts and little ammonia to color the solution to a light yellow. This mixture is well shaken, filtered with care and mixed with a spatula on a sheet of polished metal — zinc or aluminum — which has previously been cleaned with whiting. As soon as a thin coating has been obtained, it is advisable to hasten the drying by slightly warming the plate. It is then exposed to the light under a positive, after which, the exposure being judged sufficient, the metal is taken out of the frame and inked with a glue roller charged with transfer ink that has been reduced with turpentine. The plate now appears grey without any sign of the picture. The ink must not be black, but rather thin and evenly coated. By immersing the plate in luke-warm water, the de- sign will shortly appear. A little aid to the development can be given by the use of a small piece of raw cotton, which should be rubbed gently over the plate until the design is clear and sharp. Photo-Lithography 141 The image so obtained is a negative one, and the metal is bared at the points representing the black in the original. The albumen has, in fact, remained soluble at these parts, having been protected by the corresponding lines in the positive when exposed to the light in the photographic frame. The plate is then rinsed with plenty of water, dried, and plunged into a solution of perchloride of iron at 35 degrees B, in which it should remain from ten to fifteen seconds. It is then washed again and dried. Upon again passing over the plate, which has been slightly heated, a roller charged with transfer ink, the ink adheres over the whole surface. A black picture is thus made, after which the deep parts are brought out by the aid of a smooth roller passed rapidly over the surface of the plate a few times. The picture is again developed by rubbing the surface of the plate with a piece of muslin that has been soaked in caustic ammonia. The design will now appear reversed, the image being in black, standing out from a brilliant background formed by the metal. During this operation the bichromated albumen insolubilized by the light, dissolves in its turn in the ammonia, and a second development is thus operated. By the rubbing, and the aid of the ammoniacal liquid, the ink is removed from the parts at which the insoluble albumen is prominent, while the ink remains upon the perchloride of iron. The plate is now prepared in the or- dinary way for lithographic printing, rolled up, chalked, and etched. The metal plates used for this purpose are first well cleaned with benzine to remove all traces of grease. They 142 Metal Plate Printing are then coated with a solution of asphalt, using a whirler to obtain an even coating. When this is properly ac- complished, the plates will have a golden appearance, and are then ready for printing upon through the negative. The necessary time for exposure in sunlight is about four minutes, and about twelve minutes in diffused north light, between io a. m. and 2 p. m. The thicker the film, the longer the exposure. The photo-printing frame must be of strong con- struction, with a pad of thick felt placed behind the plate to ensure perfect contact. After the exposure the plate is developed in a zinc dish, with French or Neustadt oil of turpentine. De- velopment is rapid, and usually takes from one to two minutes. In developing over-printed metal plates, an ad- dition of Russian turpentine is of great assistance. After development the plate is well washed and whirled to free it from water, and it is then dried in the sun for about a quarter of an hour. It is then etched in a one per cent, solution of nitric acid; leave in the bath for about one minute, well wash with plenty of water, drain, gum up, and dry quickly. The plate is allowed to stand for fifteen minutes, and then the gum is washed off and the plate is inked up with a soft ink. If the asphalt design does not take the ink freely, resort must be made to the rubbing-up rag charged with the ink and & little grease (such as palm oil) if necessary. When inked-in satisfactorily, wash the plate with water, dry quickly, and dust over with French chalk. The plate is then etched with the usual etching solutions, gummed up, and dried. Ph oto-Lithograp hy 143 It can then be washed out with oil of turpentine — without removing’ the gum coating — inked in solid, and rolled until clear by adding a few drops of water; then gum up and dry. Allow the plate to rest for fully an hour, so as to allow the work to become set upon the metal. At the end of that time the plate is ready for printing. If the plate is not accurately treated, it will scum in the rolling-up, and give dirty impressions. When such is the case, roll up the design, dry, French chalk, and etch with a weak solution of acetic acid; then rinse well. In printing from machine it is advantageous to add a small quantity of glycerine to the damping water. When it is found necessary to make alterations or additions to metal plates already in use, they should be well rolled-up and French-chalked. If any parts of the design are to be erased, wash out those parts with turpentine or benzine. Wipe perfectly dry and apply a small quantity of caustic soda solution to the plate by the aid of a camel-hair brush. When it is apparent that all trace of grease is removed, wash the plate, and then re- peat the operation to make sure of its cleanliness. After this, run over the plate a solution of citric acid, wash well with plenty of water, and dry quickly. It is then ready for the new work to be transferred or drawn upon it. After the alterations are completed, gum up the plate thoroughly, fan dry, and proceed as before described. Still another process that may be used for photo- graphing direct on the plate or stone embraces the prin- cipal of printing on to light-sensitive asphalt or an or- 144 Metal Plate Printing ganic substance in combination with a bichromate salt. This light-sensitive asphalt, or so-called Syrian asphalt, which is prepared for photo-lithographic purposes, can be obtained from various firms who deal in photographic goods. Only that part of the asphalt is sensitive for photo-lithographic work which does not dissolve in ether. The insensitive part must, therefore, be separated out, which is done by finely powdering the asphalt, sifting it through a fine sieve, then treating it with ether. All that is soluble in ether goes into solution; the marc which is not soluble in ether is then dissolved in benzole and used as wanted. Professor Husnik has improved this process insofar that he does not dissolve the asphalt powder in ether, as, according to his view, a complete solution of all the insensitive portion is not attained by this process, but he dissolves coarse asphalt powder completely in rectified spirit of turpentine to the consistence of a moderately thick syrupy mass, until no hard particles or a residue are contained in the solution. To this viscous asphalt solution a plentiful quantity of ether is added gradually, and with constant stirring; and a large bottle should be used for this purpose. After a sufficient quantity of ether has been added a pitch like deposit separates out at the bottom. In order to test whether there is still any light sensitive asphalt in the supernatant liquor a small quan- tity is poured into a glass and mixed with ether, when if a precipicate ensues more ether must be added to the large bottle. After standing for about twenty-four hours the ether contains all soluble insensitive constituents of the asphalt, the pitch-like residue in the bottle, after pour- Photo-Lithography 145 ing off the solution is again treated with ether, A so that all turpentine is extracted and any stray and sensitive par- ticles are dissolved. The pitchy residue is now removed from the bottle and allowed to stand in a porcelain dish in a warm place, with frequent stirring, till it is quite free from ether, and has formed a hard, brittle, black shining substance, which can be easily broken up into powder with the hand. This product is now the light-sensitive asphalt, which is dissolved for use. in anhydrous benzole. As benzole is only to be obtained anhydrous with dif- ficulty, some chloroform is added to the solution in or- der to prevent the running together in drying, whence the film would become unequal and patchy. The coating of the plate or stone with the asphalt film is very sim- ple; it should be placed horizontal, then whirled rapidly on a whirler. The picture is developed with turpentine in following out this process. Valenta recommends for photo-lithography an as- phalt which has been sulphurized by the wet process, as it possesses, he says, a considerably higher light-sensi- tiveness than that which is not sulphurized. This process is as follows: ioo g. of raw Syrian asphalt is boiled in a retort with an equal quantity of raw pseudo-cumene which has the formula C6H3(CH3)3, and a boiling point of about 170 C., with 12 g. of flowers of sulphur, which should have' been previously dissolved in the pseudo- cumene. When after about three or four hours boil- ing the evolution of sulphuretted hydrogen has ceased, the pseudo-cumene is distilled off and the black pitchy residue dissolved in benzole in the proportion of four to one hundred and used for the preparation for the plate 146 Metal Plate Printing or stone. The sulphurized asphalt prepared according to this method is almost insoluble in ether, but dissolves fairly readily in benzole, toluene, xylene, cumene and turpentine, and is very sensitive to light. Good prints are said to be obtained from this scheme in bad, cloudy weather. For developing the asphalt image rectified oil of turpentine free from acid is used and it may be ac- celerated by adding Hungarian or Russian turpentine mixed with ligrion, benzine or wool oil. There should be no rubbing with cotton wool, etc., in using this pro- cess. Metal plates are best developed in a deep dish, while with the stone a wax margin should go round the draw- ing. After the development the plate should be well washed under a stream of water and before gumming the plate should be exposed for some time to light as this makes the ground more resistant to etching. In coating the plate or stone with one of the above solutions it should be spread thinly and allowed to flow over the surface so as not to form unequally covered patches. The subsequent manipulations should be con- ducted in the dark. Metal plates for deep etching must be well grained and polished and ought not to repel water. The plate is, after development, well washed, then allowed to dry, treated with thin gum solution, then with etching solu- tion of tincture of galls or gallic acid and phosphoric acid and inked up. Prints on metal plates for deep etching are gummed after development and, if the asphalt film is perfect, with- out rubbing up with a pad, which thickens the drawing. Photo-Lithography 147 It should be etched for some minutes in very dilute nitric acid. Many lithographers are accustomed, and indeed, it is necessary with some transfers, to rub the prints up with greasy ink. This process is as follows: Greasy transfer ink is diluted with some turpentine, and after the stone or plate has been gummed and allowed to dry and then washed, the drawing is wiped over with a soft pad saturated with the dilute ink when the ink ad- heres to the drawing, which strengthens it. If great care is not taken in this process it will also thicken the work. With asphalt prints this method is absolutely un- necessary and for other direct prints, as well also as for good chromated gelatine prints, this practice is use- less. The exposed asphalt combines so intimately with the plate that strengthening with greasy ink is quite superfluous; is, indeed, absolutely purposeless, as the ink can neither penetrate the hard asphalt film nor combine with it. The film of asphalt alone is so resistant to every etching solution that it is for this reason entirely useless to strengthen it. Besides the asphalt, other mixtures of other light- sensitive substances may be used for direct printing, and these are mostly organic substances in combination with a chromium salt, and possess also a greater sensitive- ness to light than asphalt. In making half-tones for the offset press an entirely different method is adopted from the same kind of a plate for the type press. In fact such fine work is being done from half-tones on the offset press that some photo- engravers are beginning to make plates especially for 148 Metal Plate Printing that process. This is done by working direct, thereby avoiding the necessity of reversing the transfers. The photo-engraver, in making a half-tone plate for the type printer, reverses it in the process of preparation by stripping the film from the plate of the camera, turn- ing it over and laying it face down, causing the letter- ing to come out on the plate reversed and when it comes out on the printed sheet, it of course, appears properly. In making a plate for the offset press this reversing pro- cess is omitted, the reversing being done naturally when the transferrer puts down the transfer on the metal plate. A capable transferrer need have no trouble if he will be particular to use none but first-class transfer paper in the work of reversing. Poor, old transfer paper causes more trouble in the shop where the offset press is used than any other thing which enters into the work. In case he is called upon to make a photo-lithographic trans- fer the transferrer should remember that this transfer paper is a specific article in every respect, the coating of which consists of a gelatinous emulsion, which can be readily sensitized, and upon which a photographic image can be developed. A bichromated, gelatine paper can be obtained by coating a hard writing paper of me- dium thickness with a gelatinous solution consisting of one ounce of gelatine and one ounce of water, and after- wards sensitized with bichromate of potassium. It is better to use the commercial varieties of paper and sen- sitize it as required. The sensitizing solution can be prepared by dissolving one ounce of bichromate of potas- sium in 20 fluid ounces of water. Add to this sufficient ammonia to give it a bright orange color. Keep this so- Photo-Lithography 149 lution in a temperature of about 60 degrees Fahr., and float the paper on it for about one minute. Pin or clip the paper to a board or squeeze it to a glass and dry in a dark room. Correct exposure and sufficient illumination of the copy are always important factors in photographic re- productions of any kind, but they are of infinitely greater importance when applied to photo-process reproduction. One is, to a certain extent, dependent upon the other. The former must of necessity be controlled by the latter ; yet no amount of exposure will compensate for defective illumination. Where artificial light is employed the ad- vantage of using two lights is obviously great. Apart from the greater brilliancy and intensity of the light the illumination of the copy is more evenly distributed. In scraper-board copies no shadows are thrown from the embossed dots or lines, and the granular texture of grained papers is entirely eliminated. The original for reproduction must be on the same optical plane as the sensitive plate in the camera ; that is, they must be on the same parallel. One of the latest inventions calculated to improve photo-lithography is a French process by which the inventor affirms that he can give results which are per- fect as to gradation of tint and fineness of modeling, reproducing with the greatest fidelity all the detail and tone of the photographic negative. The surface of the stone or plate is first finally grained by the methods ordi- narily employed in lithography, and it is important to obtain a grain of absolute uniformity and regularity. After the graining there is a process of cleaning up by 150 Metal Plate Printing means of a weak solution of nitric acid, and the sur- face is then rapidly dried. It is then slightly warmed, and the surface thinly covered with a preliminary coat- ing of gelatine, the stone or plate being then maintained at a temperature of forty degrees centigrade, or one hundred and four degrees Fahrenheit, until completely dry. A solution of albumen, twenty parts, saccharic acid, ten parts, to water two hundred parts, is then applied over the substratum of gelatine and dried. Two other solutions are then prepared, first chrysaniline, 2 grammes, chloride of zinc 50 grammes and water 100 c.c. The second solution is made up of bichromate of potash 14 grammes, bichromate of ammonia 30 grammes to water 1,000 c.c. For use in mixture equal parts of the two solutions is taken, and this is flowed over the stone or plate, which is then raised to a vertical position to allow the excess of the solution to drain off. When the coat- 1 ing is dry, the exposure is made under a photographic negative; in a good light of normal intensity the ex- posure varies from ten to fifteen minutes. A special ink is made for rolling up, consisting of convenient pro- portions of lampblack, Venice turpentine, and black writ- ing ink, mixed while made hot, and to which is also added a paste composed of bitumen and resin powdered very fine, and beef fat. This ink is well distributed with a hard roller, and the surface of the stone or plate well rolled with it all over. The image is developed by pass- ing very lightly over the surface a sponge saturated with water. When the print has been developed clean, the stone or plate is then well gummed and dried. The sur- face is sponged over to remove the gum, the ink cleaned Photo-Lithography 151 oft with turpentine, and the work is then etched with a weak solution of nitric acid for removing the sensitive film. It is to be remarked that with this process the photographic image is applied direct, the coating which has served for sensitizing being destroyed by the appli- cation of nitric acid before the last inking. The method is said to be excellent for the perfect reproduction on stone and metal of photographs from nature, pen and ink designs, water colors, etchings, etc., and can be ap- plied with success to three or four-color work. The most convenient method for a lithographer work- ing on stone to follow to convert a positive printing image into a negative is the following: A good stone is first ground in the ordinary way and then the surface rubbed with a pad and oxalic solution till it has a high gloss or polish. On to this stone is then transferred sharp impression in a non-greasy ink from the positive printing image. According to the destination of the stone for large or small editions one of two processes may be adopted. If a thousand or more pulls are required from the stone the transfer may be dusted with resin powder, and this melted with the burning, heating, or ether pro- cess and the drawing etched in relief with 8 to io nitric acid and gum. Then the stone may be well washed with water and the acid removed with one to two per cent, acetic acid. For small runs the etching is omitted and the stone treated with ascetic acid. In both cases the stone should be well washed, dried, and then coated with dissolved lithographic tusche or autographic ink. The greasy substances of these materials penetrate into the surface of the stone that is laid bare, and firmly 152 Metal Plate Printing adhere. When the tusche or ink is completely dry the stone is washed with turpentine, inked up, and one now has a negative image from the subject in question which shows all the original printing places in white and all white places black. The facts contained in the foregoing are all impor- tant factors in photo-lithography, and their importance and influence upon the reproduction of originals can scarcely be overestimated. 1 Solutions, Formulas and Useful Information Epitomized E TCHING and other solutions used in metal plate printing are supplied by those who manufacture the various plates, and it is well to use such, and follow out the directions given by the manufacturers. It is only reasonable to suppose that those who have passed through the experimental stages should be able to give the best means to attain the desired end. After some experience in working some modifications of the ap- pended recipes will very likely be found to answer as well, if not better, than attempting to carry out literally the directions given; careful observation and practice will greatly assist the printer in these matters. There are various solutions necessary for the proper working of metal plates. They are not of a complex nature, but at the same time it is imperative that they should be carefully attended to, if successful printing from these plates is to be obtained. For those who wish to prepare their own plates the following formulas are given. When the plate has been roughened and attains a smooth, even grain, the following solution is prepared: Concentrated solution of alum, 20 parts; phosphoric acid, 2 parts, and 20 parts of water ; or alum solution, 10 153 154 Metal Plate Printing parts, gallic acid, 15 parts; nitric acid, 2 parts to 30 parts of water. After the transfer the plate is gummed and then etched with an etching solution consisting of 10 parts of gallic acid, 2 parts of phosphoric acid, 10 parts of gum solution, to 30 parts of water; this being allowed to act for 30 or 40 seconds. The photographic-lithographer will frequently require the lithographic Tusche for additions or for corrections. The Tusche must be tolerably brittle and dissolve in distilled water and flow fine and clean from the pen. These ingredients should be melted to- gether by boiling : 2 parts of yellow wax, 2 parts of mut- ton tallow, 6 parts of Marseilles soap, 3 parts of shel- lac, and V2 part of lampblack. A good autographic ink which draws in brown may be obtained from the following formula: to parts of Marseilles soap, 10 parts of tallow, 12 parts of shellac, 12 parts of yellow wax, 5 parts of mastic, 4 parts of asphalt, 3 parts of vinesoot, to 125 parts of water. Origi- nals prepared with this ink transfer as well immediately as after several months, and ordinary well-sized writing paper can be used for drawing or writing on. Fatty crayon used by photo-litho work is composed of : 30 parts of wax, 24 parts of Marseilles soap, 4 parts of tallow, 1 part of shellac, and 6 parts of lampblack, while lean crayon consists of 12 parts wax, 8 parts Marseilles soap, 2 parts tallow, 10 parts shellac, and 4 parts lamp- black. Any good transfer ink can be used for a developing ink, as this is applied with a roller. It usually consists of equal parts of tallow, wax, soap, some resin, and as Solutions, Formulas, Etc. 155 much lithographing ink as all the other ingredients put together. Thin developing inks can be prepared by diluting good transfer ink with equal quantities of wax, benzine and turpentine. The following formulas are given for etching or desensitizing solutions: Original etching solution, 12 parts gum solution and 1 part, 20 per cent, phosphoric acid. This is a weak etching mixture, and a few drops of red ink should be added to color it, so that it may be easily distinguishable from the stronger solution. A Transfer Etching Solution: 8 parts gum solution and 1 part, 20 per cent, phosphoric acid. Both of the above formulas should be prepared two or three days before they are required, and well shaken or mixed before using. An Aluminum Counter Etching Solution : Add crystallized oxalic acid to a pint of warm water till a saturated solution is obtained; that is, until the crystals have dissolved. Then mix 4 parts of this acid with 96 parts of distilled water. A good cleaning preparation may be obtained by pul- verizing finely 4 parts of crystallized oxalic acid and 4 parts Terra di Siena, and dissolve in water. Apply with quill or glass hair pencil. Concentrated sulphuric acid may also be used as a cleaning preparation. An Acid Bath, consisting of 1 part nitric acid, 45 per cent, (must be free from chlorine) and three parts water, is very good; or the following may be utilized as a substitute: 3 parts nitric acid, 45 per cent, (must be free from chlorine), 5 parts fluorsilicic acid, and 42 parts water. 156 Metal Plate Printing As a washing-out fluid, melt over a moderate fire these ingredients: io ounces of yellow wax, 14 ounces of Venetian turpentine, 4 ounces of tar, and 18 ounces of the best black ink. When the whole is melted and in a liquid state, add, while stirring, 36 ounces of pulverized asphalt, dissolved in 1 pint of Benzoline. The mixture is then diluted with 10 pints of turps and is then ready for use. For a smaller quantity than the above recipe, the proportions may be halved or quartered. The following recipe for the same liquid is given by another expert: Dissolve 1 ounce of wax, 1 ounce of Stearine, 2 ounces of asphalt, 1 tablespoonful o'f Tere- bene, \]/ 2 pints of turpentine, and y 2 ounce of re-trans- fer ink. The reader will notice that in the recipes for the washing-out fluid there are two distinct classes of ingre- dients. First, the grease solvents; secondly, the greasy bodies which do not evaporate, but will, with the aid of the solvents, be spread over the work, which thus re- ceives a coating of greasy matter which strengthens the transfer, and enables it to take on more readily the ink for further preparation, while, at the same time, the dry gum still remaining protects the other parts of the plate, so that they do not receive the grease from the solution. An affinitising bath with the following constituents is recommended: 6 ounces of nitric acid, y 2 pound of powdered alum, to a gallon of water. The alum is best dissolved in warm water. To etch after the drawing has been laid down this solution is suggested: Equal parts of ammonium silica- fluoride and ammonium nitrate. Solutions, Formulas, Etc. 157 Another good metal plate etching solution is : Nut gall solution io ounces Gum arabic solution 20 ounces Phosphoric acid . % ounce Nitric acid J 4 ounce The strength of this preparation can be altered to suit the plate. The best wash-out fluid for the transferer is said to be the following formula : Asphaltum powder 1 pound Beeswax % pound Tallow pound Turps 5 pints Benzole 1 pint Oil of tar pint Lavender oil . 1 ounce This liquid solvent when sprinkled on the roller soft- ens the black ink, and the effect is to render a less adhe- sive substance, making it more readily imparted to the greasy transfer image. Taken altogether, the very best etch for zinc plates so far discovered is a solution made up as fol- lows: Nitrate of Ammonium, 21 parts; Bi-Phosphate of Ammonium, 20 parts; Gum arabic, 200 parts, and water, 750 parts. Lithographic printing inks are generally stiff and strong in body when received from the makers and require to be reduced before they are used for printing purposes. The medium of reducing them is principally varnish, which is used in several degrees of consistency. It is prepared in various ways, but for lithographic work 158 Metal Plate Printing that obtained from the best linseed oil alone gives excel- lent results. There are various kinds of gums, gum-resins and resins, all of which are the products of different trees. To the eye some of these resemble each other so closely that it might be difficult to tell the one from the other. There is, however, this remarkable difference in charac- ter that the gums proper are all soluble in water and insoluble in spirits; while the resins proper possess ex- actly the opposite quality, being soluble in spirits and insoluble in water. These two opposite properties are invaluable in the lithographic process. The gum used for lithographic purposes should be pure gum arabic, sold, it may be, under different names which generally indicate the district from whence it came. A gum solution should not be allowed to get sour, which it will do in eight or ten days in winter and half that time in summer. There are certain preventives, such as the addition of a little camphor, carbolic acid, or the essence of cinnamon; and there is a remedy for the sourness when it has taken place, in the addition of a lit - tle powdered chalk. But by far the safest plan is not to allow it to get sour at all. This is easily effected by dis- solving only a few days’ supply at a time and keeping the sponges and pot perfectly clean. The action of sour gum is most detrimental to good work. To ascertain the good quality of printing ink you have merely to take a sheet of unsized paper and spread a little of the ink to be tested upon the surface. Some hours later the ink will be surrounded with an edge formed by the varnish. When the ink is good this edge Solutions , Formulas , Etc. 159 is invariably white, and, on the contrary, when bad it is of a more or less deep yellow color. Such ink could not give satisfactory results in printing. This yellowness is sometimes due to defective boiling of the varnish or im- perfect calcination of the black employed. These re- marks do not apply to cheap, common inks, but to inks of some value. Good ink should be black, brilliant, unctuous, too thick rather than too thin, and should dry rapidly. The finer an ink is the better its siccative properties. Petro- leum should never be added to ink to make it less strong. The degree of strength or excessive siccativeness can be reduced by mixing the varnish with the ink. Good recipes for paste and glue, which are the result of experience, are given below: Dissolve half an ounce of the purest white glue in half a pint of rain water and add four ounces of the lumps of gum arabic. This is a good glue for pressmen and for general purposes. To make it pliable for setting gauges and for bookbinding, where a quick-drying glue would not answer, add a little glycerine. You can whiten common glue by adding oxalic acid. A fire and water proof glue is a handful of quick- lime mixed with four ounces of linseed oil, thoroughly mixed, boiled to the consistency of syrup and spread on thin plates in the shade. It hardens and is then dis- solved like common glue, when it is ready for use. A fire, water, weather, acid, and rust-proof cement that can be used to fasten nearly every imaginable sub- stance— metal, glass, woods, etc. — is litharge and glycer- ine mixed to the consistency of thick cream. The mended or joined articles should not be used for from a day to a 160 Metal Plate Printing week, according to quantity of cement used, as it is a slow drier. A fine paste — none better for trndery and press work, especially for rotary presses — is made by mixing good flour with rain water, rapidly boiling to a paste and adding a little carbolic acid, the best preventive of sour- ing. Do not use alum, acetic acid or borax, as some do, for this purpose. Strain the paste through a very fine sieve and it is ready for use. Tusche, or litho drawing ink, is something that every lithographer should know thoroughly. The main thing is that it should contain fat and soap ; the first substance is put in for the purpose of resisting acid, which must be applied to prepare the clean litho surface upon which it is used; the second substance is placed there to combine with the plate or stone, through the action of nitric acid, into a saponacious material, resulting in that strong, per- manent hold which the work then obtains. In order to fulfill this requirement, the soap used for making such ink should contain the greatest amount of oil in combina- tion with alkaline bodies ; or, in other words, fatty acids, and for this reason Marseilles soap, which contains nearly 20 per cent, more of this acid than the ordinary soap, is preferred by some in making this ink or litho Tusche. In addition to this there is wax, or spermacetti, added also for their greasy qualities; further shellac, pitch and mastic, to help bind the first-mentioned material together, and finally, as it would be impossible to draw fine lines, dots, or close textures with an almost colorless fluid, lampblack, in its finest state of reduction, is added simply to give color. The greatest amount of care should be exercised in the mixing, owing to the diversity of the substances used. Advertising Section 163 Metal Plate Printing No Graining or Preparing Required Parker Process Plates The Only Concern in the World Making a Specialty of Lithographic Plates and SOLUTIONS WRITE FOR PARTICULARS Parker Process Company 536-538 Pearl Street, New York, N. Y. 385 Dearborn Street, Chicago, 111. 230 St. Clair Avenue, N.E., Cleveland, Ohio 23 Jarvis Street, Toronto, Canada 164 Metal Plate Printing The Fuchs & Lang Mfg.Co. 29 Warren Street, New York 328 Dearborn Street, Chicago 44 High Street, Boston 150 N. 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