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The Complete Book of SILK SCREEN PRINTING PRODUCTION
By J. I. BIEGELEISEN
Dover Publications, Inc.Copyright © 1963 J. I. Biegeleisen.
All rights reserved.
BRIEF HISTORY OF THE PROCESS
IT IS too bad that the discovery of the silk screen process cannot be associated with some heroic figure of the legendary stature of a Gutenberg or a Senefelder. There is a definite date marking Gutenberg's historic discovery of movable type. The year was 1450. Senefelder is said to have stumbled on the accidental discovery of lithography by writing a laundry ticket on a grease-coated stone, back in 1796. As for silk screen, it has no classic and definite heritage. No godfather attended its christening. No indisputable record has been traced to mark its date or place of origin. Perhaps it may be best to console oneself by saying that though the process may have had a vague past, it has a brilliant future. It is now generally recognized as one of the major graphic arts along with letterpress, lithography and gravure. And the commercial process as we know it today actually started only sixty years ago.
Though no one man's name or no one place of origin is credited with the discovery of silk screen, there are writers in the field who attribute the process (in its earliest form) to the ancient Chinese and Egyptians, who employed open stencils for applying ornamental decorations to fabrics, wallpaper and walls. Their stencils were not really silk stencils; rather they were sheets of impervious materials cut to form an open design. Dyes and other media were brushed over the openings of the stencil, resulting in a facsimile "print." The nearest early prototype of the method employed today of which we have positive evidence were the stencils made by the early Japanese—a method which has continued until the advent of the stencil mounted on silk (the beginning of the screen process as we know it today). The Japanese stencils consisted of oil-treated heavy paper sheets through which openings were cut in rather intricate detail. To keep the isolated parts of the cut paper from dropping out, the Japanese printmaker painstakingly glued a spider-like network of human hair across the openings, thus keeping all of the integral parts of the stencil intact.
The method of cutting stencil openings on impervious sheets, such as oiled paper, metal, etc., has been known and used by many peoples throughout the centuries. Up to this very day, decorations and lettering are still applied to walls, simple sign boards and packing crates in that way. This type of stencil is characterized by little ties or bridges of the stencil tissue which keep the island parts of the design suspended. A print made with such a stencil shows gaps or breaks which interrupt the continuity of the design.
In a way, the early Japanese hair-crossed stencil may be considered the antecedent of modern silk screen. The Japanese stencil maker did not use conspicuous ties in his design structure. The strands of human hair which held the isolated parts in suspension were so fine that their presence was hardly discernible in the finished print. The loose paint brushed over the stencil flooded the openings sufficiently to result in a continuous unbroken design.
The principle of using an invisible web of strands of hair as a carrier or screen for the stencil image (in order to eliminate conspicuous ties) was the forerunner of the modern screen stencil. The silk screen today is, after all, nothing more than a ready-made web or meshwork of strands, not of human hair, but of finely woven silk threads. Experimental work using woven silk as a screen was done in Germany and France as far back as 1870 and was then carried on in England. It is a matter of record that a patent related to silk screen was granted in 1907 to a Samuel Simon of Manchester, England. The Simon patent covered the use of the screen as a carrier for the stencil but it did not include a squeegee. Simon used a bristle brush instead of a squeegee to force the paint through the silk.
Although the process had its uncertain beginnings in China, Japan, Germany, France and England, it is in America that it was first developed and exploited as a commercial craft.
In America, though no one man was granted any controlling patent on the basic principle, much activity in the development of the process took place on the West Coast. In 1914, a multicolor screen process was perfected by a commercial artist named John Pilsworth of San Francisco, who later, in collaboration with a Mr. Owens, was granted a patent for screening several colors from a single screen. This was known and commercialized as the Selectasine method and was developed into a thriving business.
From California, the use of the process spread eastward. At first, it was looked upon as a tedious process requiring too much painstaking effort for practical commercial work. During the teeming activity of World War I, the process was taken up by sign painters and decorators of flags, pennants and banners. At first, the intricacies of the process were kept under cover, shared only by a select few. Any new developments, such as the photographic and tusche methods, were jealously guarded as "house secrets." These "secrets" in time became public property emerging into a fledgling industry, which was soon competing with the craft of sign painting and showcard writing. With the growth of chain stores from mere groups of four or five to twenty or thirty or more stores, the individually hand-lettered signs soon gave way to the process whereby identical signs could be mechanically duplicated in any desired quantity. As a consequence, the very sign writers who at first looked upon the process as a competitive craft began to adopt and experiment with it themselves. Many of them abandoned hand lettering altogether in favor of silk screen printing as a new and profitable specialty.
Thus the method became popularized, but unfortunately not popular with national advertisers of high-level merchandising. Compared to lithography and letterpress, the results obtained by silk screen were crude. The prints lacked quality as well as uniformity. They were identified by blurry, ragged edges. The paints used were home-made and often failed to dry. Production was at a snail's pace. An automatic screen printing press was patented in 1925 but was not adopted by the processors. The trouble was that the screen paints used in those days dried too slowly to keep up with the output of the machine. The machine produced faster work, but the quality of the prints was no better than that achieved with the manual printing units. Advertising agencies for the most part wanted no part of the process since the results did not measure up to the standards of highly developed lithographic or letterpress methods.
A milestone in the process was reached in 1929. In that year, in Dayton, Ohio, a screen printer named Louis F. D'Autremont developed a knife-cut stencil film tissue which was patented by an associate, A. S. Danemon. They called this film tissue Profilm. At first they used it in their own print shop, and later marketed it for national distribution. With the use of this knife-cut film tissue, it was possible to overcome one of the important drawbacks to the process; namely, the ragged unsharp print quality which had heretofore been associated with silk screen. It is true that even at that time and before, screens could be made photographically with acceptable sharpness and fidelity of line, but the photographic method was cumbersome and as yet undeveloped. It was the introduction of Profilm, therefore, which made the process take a new turn.
Several years later, Joe Ulano, a young man who was at that time a foreman in a New York screen shop developed a film which he patented as Nufilm. This patent was contested in the courts by the manufacturers of Profilm. Ulano lost the verdict, but won the prize. He was to become a licensee of the Profilm Company, but in a short time so perfected his own film that it was widely accepted as the standard here and abroad. The Ulano Nufilm was easier to cut, adhered more easily to the silk, and was more efficient time-wise, than the original Profilm.
This favorable turn in the development of the industry has served as an inducement for important paint manufacturers to look upon the process as a good potential market for specially formulated paints. Heretofore, the total dollar value of business for paint manufacturers was not attractive enough to be taken seriously. Now, efforts are made to formulate complete lines of paints for screening on paper, board, glass, textiles, and every other one of the growing number of printing surfaces to which the process could be applied. Heretofore, the paints used in silk screen were for the most part self-formulated mixtures of coach or japan colors, crudely ground pigments, lithographic oils and other compounds not refined for the process. These colors required hours of drying in racks. Indeed, some obstinately refused to dry at all-and production of printing was geared to the drying time! Today, paints and other compounds are formulated to air dry within ten minutes or force dry within seconds.
As a consequence, or perhaps concomitantly, there has for the last fifteen years been an awakened interest in fast automatic screen presses capable of production speeds of 2000 to 3000 impressions an hour. These presses work in tandem with conveyers and drying ovens where the prints are ejected and stacked—all without human effort or physical exertion. Although the trend towards automation is presently going on at a rapid rate, it is safe to predict that standardized automatic screen presses will never completely replace the manually operated printing units. It is interesting to note that many screen printing establishments which have automatic equipment on the floor very often still resort to hand- operated equipment. Why? The answer will be evident in the following statement of facts.
One of the selling features of screen process is that it can print on any material, any size, any thickness of stock, any color compound, any quantity. Five "any's." One need not be an M.I.T. graduate to figure out that one type of machine could not possibly do all that. While it is true that there are special machines to do each type of work, one machine cannot be that flexible. Take the matter of size. With screen process, it is possible to print a short run of five hundred cloth banners, each twenty feet long. The wooden screen frame, which is comparatively easy and inexpensive to construct, is built to accommodate the corresponding dimensions of the job. It may prove practical to construct this special printing frame even if the equipment is not intended to be used again for a long time—or ever. It would take a colossal mechanical leviathan to produce this jumbo-sized job by machine. The quickness by which a screen frame is constructed makes it possible for the processor to accept a versatile type of work, size-wise.
There are special automatic machines for printing on cylindrical objects. There are some excellent machines for screening decalcomanias which may also be used for printing on other thin stocks. That is, again, fine for the specialist. However, the average processor is no specialist. His facilities must be easily adaptable to any type of work which comes his way. Therefore, he cannot eliminate hand-printing units because in so doing he diminishes his versatility. The average processor will gradually introduce some mechanical automatic equipment but at the same time hold on to the flexible manual equipment whereby he can render a broad service to his customers. However, it is none the less true that with the continued development of better and faster automatic screening and drying equipment, the industry will branch off into specialties. That is happening already. There are organizations blueprinted and set up solely for screening 24-sheet posters, others which do nothing but ceramic ware, or wallpaper, or container printing, or metal signs or one of a multitude of other fabricating specialties.
It is a credit to American ingenuity that the United States, which was historically late in entering the field of screen printing, has taken the lead in converting a crude hand craft into a major industry with an output of over three hundred million dollars per year.
This lead is not only in terms of annual output or number of people employed. It applies equally well to organizational ability in education and industrial cohesiveness. The Screen Process Printing Association, International (S.P.P.A.), organized in the United States in 1948, represents the keystone of the industry the world over. The annual conventions are attended by processors from every land where the process is employed. This world-wide trade organization has brought together "competitors" and caused them to work together on an amicable basis, to raise the prestige of the industry through technical research and good public relations with the advertising industry. The S.P.P.A. International's periodical literature and published manuals, widely distributed to members and schools, represent the best in collective thinking and recorded data on the technical developments in the field. Textbooks on the subject by such outstanding practitioners as Bert Zahn, Harry Hiett and Albert Kosloff have helped immeasurably to popularize the process among those whose curiosity in the subject was a natural prerequisite for instructional help. I should like to feel that I, too, have helped in this respect through the authorship of several textbooks in the field. Screen Process Magazine, the official trade magazine, is distributed the world over and has helped to acquaint the public with new developments in techniques and materials. Courses in screen process are now offered in many high schools and colleges.
Bouquets should also be extended to the many suppliers in the field—ink makers, machine builders and photo technicians, for their part in helping to nurse this infant industry through its swaddling days and fostering its growth to the status of a respected adult member in the family of graphic arts.CHAPTER 2
BASIC EQUIPMENT AND TOOLS
IT HAS been said that you can start in the screen process business on a "shoe string." Perhaps there are "strings" attached to that assertion since, as we shall see in a later chapter, automation is slowly changing the complexion of this business from a simple manual craft to a big industrial enterprise. It is true, however, that the basic printing equipment necessary to get started is simple and far less costly than for any other comparative commercial printing process you can name. The basic working screen printing unit consists of a silk-stretched frame, hinged to a flat board which is its printing base. That, and a rubber squeegee, comprise the "press." While this is theoretically true, however, the average screen processor doing commercial work expands his inventory of equipment and enlarges his production facilities to include most of the items mentioned in this chapter. Let us review the major areas of equipment by categories, such as screen frames, printing bases, squeegees, hand tools and accessories, etc.
The screen frame may be made of wood or metal. By far the greater number of frames used in manual printing are made of wood.
The wood frame consists of four pieces of 1" x 2" strong, knot-free wood, rigidly constructed so as to be free from corner twists. Wood strips selected may be spruce, cypress or white pine. The wood must be free from warpage; it must be well-sanded and preferably of kiln-dried stock. The thickness of the frame strips is not fixed. A larger frame will require heavier wood to withstand the proportionately greater pull of the silk. Figures 1 and 2 show several interlocking corner joints recommended for rigidity in professional screen frame construction. Figure 3 shows a special type of grooved frame. This type of screen frame requires no tacks or staples; instead, it is designed to be used with a special cord which is wedged into the groove, thus holding the silk in a hoop-like manner. This frame is mentioned further in Chapter 8.
Various types of machine-tooled metal frames are available. These are more widely used in standard sizes to fit frame carriages on automatic screen presses. Metal frames are considerably heavier than wood and much more costly, but they have the advantage of rigidity, an important factor in close tolerance register. They are also used frequently with special stretching devices for stainless steel screens employed for screening cylindrical ware, circuitry and other industrial printing jobs.
Excerpted from The Complete Book of SILK SCREEN PRINTING PRODUCTION by J. I. BIEGELEISEN. Copyright © 1963 J. I. Biegeleisen.. Excerpted by permission of Dover Publications, Inc..
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