Printing Production

PRINTING PRODUCTION, production of various kinds of printed publications, encompasses a number of diverse manufacturing processes that differ significantly in nature and their inherent professional hazards. The number of workers engaged in printing production in the USSR ranges from 85 to 100,000 people. Production process. The material used for casting type is the so-called "type metal" or printing metal. In the USSR and abroad, depending on whether the metal is used for casting type on hand composition machines, Monotype, Linotype, Intertype, etc., or for stereotyping work, as well as depending on the print run, type metal of the following composition is used: lead - 55-85%, antimony - 8-28%, tin - 3-20%. The function of antimony is to give the metal hardness, and tin is to give it necessary viscosity. The melting point of type metal is 270-410°; the average percentage of loss is 0.5. In the USSR, one of the following typical recipes is used: lead - 75%, antimony - 18%, tin - 7%. For stamping on bindings, type and various kinds of decorative ornaments are cast from yellow copper (properties - high melting point and hardness). Usually, for the production of printing type, lead is first melted in kettles, and the other components as well as old scrap are added; the alloy is poured into small ingots that go to the type-casting machines. The basis for obtaining the face of the type is the artist's drawing, which is reproduced by the engraver in a mirror image on a steel bar (punch). With the help of punches, copper matrices are made, in which the face is obtained in positive form. The basis for obtaining the body of the type are casting molds. The combination of matrices and casting molds in the technical production process of casting results in type. The process of casting type itself consists in the fact that a stream of molten metal is injected at certain short time intervals into a mold where a matrix is inserted, it is immediately cooled and ejected onto the composing stick. Along with type, spacing material (spaces, reglets, quadrats, quads, and etc.) is cast, which is used to fill gaps and empty spaces, as well as rules, decorative ornaments, etc. The most important process in printing, in which the largest number of workers are employed, is hand and machine composition. In a 7-hour working day, 1 compositor can produce up to 14,000 characters. The highest composition productivity is achieved from composing machines. The average productivity of Monotype is 60,000 characters, Linotype - 60,000 characters, Typographer - 38,000 characters. For printing multi-run newspapers, books and other publications, the so-called stereotype - a copy from the printing composition, cast in the form of a solid plate - is used. To obtain a stereotype, first a matrix - a paper copy of the composition - is prepared; the matrix is inserted into the casting machine mold, molten stereotype metal, pre-melted in a kettle, is poured into the space between the cover and the matrix; the stereotype is then removed from the mold and goes for final finishing, after which it goes to the printing department. For large print runs, the stereotype is galvanoplastically plated. There are many types of printing machines. The printing process consists in the mechanical application of ink to the printing form and the transfer of the ink impression from the form to paper. Depending on the nature of the printing form, three types of printing are distinguished: relief (hand and machine composition, line clichés, autotypic, xylographic, etc.); intaglio (mezzotint, classical engraving with a burin, etching, etc.); planographic (lithography, offset, phototype). Printing machines are classified as follows: 1) platen, 2) flat-bed, 3) semi-rotary and 4) rotary. Flat-bed machines are distinguished as single-revolution and double-revolution, single-color and multi-color. Rotary: single-, double- and multi-cylinder, of constant and variable format, etc. Both flat-bed and rotary machines, depending on the type and complexity of construction, give different productivity: thus, a hand press gives 50-100 impressions per hour, an "American" press - 700-1,400, a high-speed press - 1,100-1,600, a rotary newspaper press - 10,000-30,000 and more. Books and brochures are sent to the binding department, where, depending on the quality of the publication and the external appearance it needs to be given, numerous operations are performed: folding (folding and smoothing sheets according to a specific format), gathering sheets in sequence (collating), sewing, processing and finishing the spine, trimming the book, covering the book or inserting into binding, decorating the book - coloring edges, stamping on the spine and side, etc. These works are performed partly by hand, and on well-equipped enterprises almost exclusively by machines. Professional hazards in printing. Among the hazards of printing production, the main attention is paid to work with lead, with which workers in all main departments (except binding) have to deal. Workers with molten lead work in the type-casting departments - when melting type metal and casting type; in the stereotype department - when melting type metal and casting stereotypes; in the machine composition department. Workers with metallic lead work in the composition department - when composing, proofreading and distributing type; in the type-casting department - when finishing type; in the stereotype department - when finishing stereotypes; in the printing department - when setting type in the machine, when making ready and cleaning it. Both type and stereotypes consist of soft, easily abraded material, which, during manipulation with them, during friction, when trampling with feet fallen type on the floor, separates small particles that settle on the floor, on machines, at the bottom of type cases and fly into the air in the form of dust. The air in all printing departments becomes contaminated with lead dust. According to the data of authors, dust from various printing departments contains lead in amounts from traces to 16-24%, and the higher the level of air sampling, the less lead is found in the dust. Chemist Grodzovsky, when examining dust from type cases (Moscow printing shops, 1924), found 24% lead in it; in the air of the composition departments of the 1st Moscow Model Printing Shop, he found 0.8-1.0 mg in 1 m³ of air, in the MKH printing shop - 1.153 mg/m³, in the air of the printing department - 0.841 mg/m³, in the stereotype department - 0.154 mg/m³, etc. The solution of the question of whether lead evaporates from the surface of molten metal in type-casting and stereotype departments is very important from a practical point of view. Since the melting point of lead is not higher than 326°, and its alloys with antimony - 250-300°, while lead boils at a temperature above 1,000°, the formation of vapors at the temperatures at which melting is carried out in printing shops cannot be expected, although it should be noted that the temperature in the kettles here is usually much higher than required, often reaching 450-550° and even higher. When examining Moscow printing shops (1924), above the melting kettle of the type-casting shop, 0.59 mg of lead was found in 1 m³ of air, above the kettles of the Monotype machine - 0.43 mg/m³; Helder did not find lead vapors in the type-casting shop, Seitz found 0.2-0.35 mg/m³, Stakhorsky (Kharkov) - 0. Obviously, some amount of lead gets into the air here, but not in the form of vapors, but rather in the form of the smallest particles of lead oxide; the latter forms a film on the surface of molten metal in the kettles, and during manipulation (scooping with a ladle, adding new portions of metal), detachment and entry into the air of the smallest particles occurs. The next moment of danger of lead entering the workers' bodies is the hands, on which particles of type metal settle during work. Thus, Seitz (Germany, 1924) found 7-8 mg of lead on the hands of type-casters after washing, Grodzovsky on the hands of compositors - from 3 to 40 mg, on printers - smaller amounts, etc. Among other hazards inherent in work in various departments, one can note: in type-casting departments when melting type metal - emission of gases from the combustion of substances contained in raw type metal (CO, CO₂, acrolein); in type metal workers, burns from splashes of molten metal thrown out when adding new portions of raw materials contaminated with snow and moisture in winter (formation of vapors of the latter); for type-casters - standing position, strain of attention, noise from machine operation, emission of combustion products, burns (less frequent) from splashes of molten metal, exposure to high temperature (26-32-38° in the presence of high humidity), radiation from heated machines. In the stereotype department - the same hazards as in the type-casting department, but there is a greater danger of hand injuries when finishing stereotypes on round planing machines. In workers of the machine composition department - the same hazards; emission of lead dust is insignificant. For hand compositors, constant standing position, strain of muscles of the upper extremities, strain of vision and attention are characteristic. In workers of the printing department - contact with kerosene and turpentine, emission of paper dust, fumes of kerosene and turpentine; strain of vision when making ready the form. For the feeder - constant standing position, a number of dangerous moments when working with the machine.

In the binding department—there is elevated air temperature and humidity, the release of paper dust, bronze dust (see Bronzing), a sitting position for some workers and a standing position for others, and a number of dangerous moments when working on machines (presses, cutting machines, etc.). Compared to workers in other 'lead' productions, printers are in a relatively more favorable position—the 'lead danger' for them is much less, the so-called lead dust in the air of workrooms is contained in small quantities. Nevertheless, if in older literature there are many indications of a higher morbidity rate among printers, which was attributed mainly to the effects of lead (tuberculosis of the lungs, anemia, etc.), here social and general hygienic factors play a very important, apparently dominant role: work in small, unsuitable, overcrowded, unventilated rooms; night work; poor housing and living conditions; the harmful habit of workers (compositors, printers, etc.) to smoke and eat with unwashed hands during work, which leads to the introduction of lead into the body through the gastrointestinal tract; the specific selection of workers—printers usually were (and are) people of weak physique who could not find work in industries requiring more significant physical exertion. The latter is confirmed by a number of data from both foreign countries and the USSR; in particular, when examining 2,100 Moscow printers (1924), a very large number of people were found with poor development of the subcutaneous fat layer and musculature, pale coloration of the mucous membranes, a flat and rachitic chest, etc., with particularly poor results obtained for compositors and a number of professions in the binding trade. In recent years, the picture, especially in the USSR, has improved for the better—both general morbidity and mortality, as well as the incidence of tuberculosis, have significantly decreased due to improved social and general hygienic conditions. However, data on the effects of lead in printing production are also found in recent materials. After presenting a number of literary materials on the study of saturnism among printers, Pieraccini (1930) concludes that the presence of lead effects cannot be denied, but it does not cause particularly severe forms of damage—chronic latent forms of saturnism with a slow course predominate; acute poisonings are observed relatively rarely. Among the examined workers in Moscow printing plants, 2.4% of compositors had colic attacks, paralysis was found in 2.1%; for female compositors, the corresponding figures were 3.4% and 5.2%, etc.—Among other diseases, there is supposedly a higher incidence of gout, cardiovascular diseases, gastrointestinal tract diseases, etc. According to Latyshev's data for 1,200 Moscow printers in 1926, the most frequent conditions were: diseases of the nervous system (in 26% of all workers), respiratory tract (in 22%), tuberculosis, digestive organs (in 34%), cardiovascular system (in 32%). Compositors often have calluses on their palms and fingers, which give rise to cracks (especially in spring) with subsequent suppurations, flat feet are very common (according to Pieraccini in 57%), varicose veins with ulcers; myopia is observed in 10-50% of compositors by various authors (in Moscow workers—15%). Preventive measures. The most radical health measure would be the complete elimination of lead from printing. In this direction, some steps have already been taken: alloys without lead or containing it in negligible amounts have been proposed (e.g., Erlich's alloy—90% zinc, 3-4% copper and tin each, 2-3% lead), but technically these alloys proved not entirely satisfactory; only spacing material—shims, slugs, reglets, etc.—can be made from more refractory materials, mainly copper and zinc. An interesting idea was proposed to replace type with plastic material. In 1924, V. V. Blinov proposed coating type with a thin layer of nickel by galvanoplasty, which should eliminate the release of lead dust, but for a number of technical reasons, this proposal has not yet been implemented. More radically, the problem is solved by the introduction of phototypesetting. Among the phototypesetting machines known to date, the 'Uger-type' has the greatest structural completeness. The basic idea of the phototypesetting machine is to obtain on film an image of the text with simultaneous assembly of the text film with negatives or positives of illustrations (imposition) and direct copying of the composed photostrips onto zinc or pigment paper. This method has not yet been widely applied in practice. Apparently, in printing, it will be necessary to work with type for a long time, so the main attention should be paid to eliminating those factors that make work with lead dangerous. Such measures are: for type-casting, stereotype, and machine composing—isolation in special rooms, mainly machines containing molten metal; arranging machines as sparsely as possible (e.g., type-casting machines and composing machines at a distance of 1.5-2 m from each other), isolating the outer surfaces of machines, covering melting pots with hoods equipped with powerful exhaust ventilation, introducing fresh air into the room, heated in winter; mechanization of type and stereotype casting (without using ladles—casting directly from pots into molds); heating furnaces and kettles with electricity; careful handling of raw materials and alloys, frequent cleaning of rooms, finishing type and especially stereotypes in enclosed equipment, and many other measures. For hand composing, the most important measures are proper room arrangement and careful maintenance of cleanliness—frequent cleaning, sweeping of cases, cleaning of cases, and the use of any hand bellows or similar devices should be strictly forbidden—for this purpose, vacuum cleaners should be exclusively used, which have already found wide practical application; proper lighting of work places—50-100 lux in the absence of glare, sharp shadows, etc.; appropriate ventilation of rooms, which is very important, as compositors are very sensitive to the effects of strong air currents; maintaining a uniform temperature in rooms not below 18°C, etc. Organized short breaks in work should be introduced. Great importance is attached to a rationally constructed type case and the correct posture of the worker (proper instruction from apprenticeship). For printing departments—ventilation of rooms, proper lighting, frequent cleaning, guarding dangerous parts of machines; the same applies to the binding department. In printing, improving social working conditions is of particular importance, to which serious attention has been paid in the USSR: arranging printing plants in suitable premises, eliminating or strictly limiting night work, providing auxiliary facilities—dressing rooms, washrooms, canteens, etc.; proper sanitary education of workers with the aim of eradicating the extremely harmful habits of smoking and eating in work premises (their absolute prohibition); not allowing women to work in type-casting rooms, not allowing adolescents to work in the most harmful departments (type-casting and stereotype), and in other departments—only as apprentices (4 hours a day); organizing proper medical selection and periodic medical supervision of the health status of workers, etc. Thanks to the energetic implementation of these measures in printing plants in the USSR, the morbidity rate of workers, both general and due to lead exposure, has significantly decreased in recent years (see the mandatory resolution of the People's Commissariat of Labor of the USSR on the arrangement and maintenance of printing and lithographic plants, May 19, 1924). Lithography. Printing of drawings is done on lithographic machines. The drawing is applied to a lithographic stone (or zinc or aluminum plate) with a lithographic grease pencil or ink, the stone is etched, moistened with water—then the printing ink will only adhere to the places where the drawing is located. For reproducing multicolor drawings, several stones are prepared—one for each color—and on each, the corresponding part of the drawing is drawn (or transferred) (chromolithography). The main hazards of lithography are: for professions engaged in stone preparation—engravers, inkers, transferers, grinders, etc.—the release of vapors of turpentine, kerosene, gasoline, used for washing ink off the stone, the release of fine sand dust during grinding, sitting position, strong strain on vision and attention; further, carrying heavy loads (heavy stones). Work in the printing department is similar to that in printing plants. Preventive measures—proper lighting and ventilation, breaks in work, etc. Photomechanics. In recent decades, new methods for reproducing illustrations and drawings have found wide application, based on photography combined with the mechanical process of printing. These methods are called photomechanical; they include photozincography, phototype, mezzo-tinto (tiff printing, gravure, or deep printing), and others.

Here, as in photographic processes and in printing, one has to deal with numerous and diverse chemical substances—solvents, developers, etching solutions, and others, many of which are dangerous poisons: hydrochloric acid, nitric acid, ammonia, potassium cyanide, benzene, xylene, and toluene, chloroform, ether, formalin, potassium and ammonium bichromates, and many others. From a sanitary-hygienic point of view, most of these productions have been studied rather poorly, and measures to combat occupational hazards have been inadequately developed. In recent years, attention has been drawn to the processes involving potassium and ammonium bichromates, which have found wide application in these production processes due to the fact that gelatin becomes light-sensitive when containing bichromates, and also becomes insoluble or more or less soluble depending on the intensity of light exposure to it: a plate or cylinder on which a drawing has been applied with gelatin-pigment is exposed to light and then etched; where the gelatin has been exposed to this action, it remains insoluble (tanned) and does not allow the solvent to pass. Contact with bichromates is possible in a number of processes: preparation of solutions, application of light-sensitive layers to plates and cylinders, manipulation of the latter, development, etching, etc. In 1929, Overton (England) found among 150 lithographers and photolithographers 70% suffering from eczemas due to exposure to bichromates; in a work published in 1931, Mayer and Engelhardt report the results of an investigation of 114 workers in various photomechanical productions: eczemas were found in 30 of them; increased sensitivity to bichromates was present in 84%; according to questionnaire surveys of 9,400 workers in German photomechanical enterprises (1930), 220 people had suffered from skin diseases, etc. Of the various photomechanical productions in the USSR, photozincography and mezzotint are more widespread. In the first process, negatives are copied onto a zinc plate coated with an aqueous solution of albumin sensitized with ammonium bichromate, or with chrome glue, after which the plate is etched with solutions of hydrochloric and nitric acids. In the last process, etchers have contact with acids and inhalation of gases formed during their decomposition (chlorine and nitrogen oxides) (no detailed studies of the content of the latter in the air have been carried out; Grodzovsky in 1925 found in one workshop a chlorine content of 0.0026 mg in 1 liter of air). From a sanitary-hygienic point of view, the recently introduced in the USSR and increasingly spreading method of mezzotint or intaglio printing is of much greater interest. The drawing is photochemically applied to pigment paper and from there to a copper cylinder, which is etched (with a ferric chloride solution) and installed on the printing machine above the inking apparatus, then printing on paper takes place. Aniline dyes of two kinds are mainly used—water-based and resin-based (or fatty), which dissolve only in benzene or in a mixture of it with homologs (toluene, xylene). The first type of dyes is not yet widely used; work is mainly done with fatty dyes, for the dissolution of which in the USSR only benzene is used, while abroad—a mixture of it with homologs in various proportions. Studies conducted in 1927 by Raeva and Ostrovsky in two Moscow printing shops showed the presence in the air of workrooms rather high concentrations of benzene: in the first—0.3-2.2 mg in 1 liter of air, in the second—0.4-1.5 mg; in workers, signs of chronic exposure were noted, later there were reports of several mild acute poisonings. In foreign, mainly German, literature, a number of reports have appeared about the chronic effects of solvent vapors on the health of typographic workers, indicating numerous complaints by workers about symptoms from the nervous system, gastrointestinal tract, cardiovascular system, frequent bleeding from mucous membranes, etc. In blood examinations, a decrease in the number of leukocytes was found in workers, and this decrease was due to a decrease in the number of polymorphonuclears, while the number of lymphocytes remained unchanged, resulting in a relative lymphocytosis. Health-improving measures in photomechanical enterprises—first of all, proper equipment and suitable premises for this purpose with fulfillment of basic sanitary-hygienic requirements; to avoid contact of workers with caustic, irritating, and poisonous substances (bichromates, acids, etc.)—mechanization of production processes, wearing of rubber gloves, greasing of hands with vaseline, frequent washing (after bichromates with sulfite or bisulfite solutions); to prevent inhalation of poisonous vapors and gases—general ventilation of the premises, carrying out processes, wherever possible, in enclosed chambers, fume cupboards, etc., equipping machines with local exhaust ventilation (especially important for such processes as typographic printing); to prevent accidents, burns, acute poisonings, etc.—proper storage of acids and other substances, careful handling of them, etc. For typographic printing, it is necessary to raise the question of switching to water-based dyes, since implementing local exhausts at machines is a rather difficult task, and it is hardly possible to eliminate the harmful effect of benzene on workers by other means.