una iCHoa The Printer's Dictionary of Technical Terms A Handbook of Defifiitiotis and Information about Processes of Printing With a brief Glossary of Terms used in Book Binding Compiled by A. A. Stewart Instructor in the School of Printing North End Union Boston, Massachusetts Published by the School of Printing North End Union I912 ^^ Copyright, 19 1 2, by Alexander A. Stewart Foreword n^'HE following pages have been in course of preparation for several years. Originally some of the matter was intended solely as "copy" for practice in type-setting by pupils in the School of Printing; later it was arranged, roughly, into the form of a brief glossary, and then, as its value for practice-work, instruction, and general trade infor- mation became apparent, it was gradually put into the form in which it now appears. The book is the product of some seventy-five or eighty young printers, who have left on its pages the impress of their first struggles to attain a mastery of their chosen vocation. Every page represents hours of patient, earnest work on the part of pupils who were receiving their first lessons in putting hastily prepared copy into typographic form. In its com- pilation no especial researches have been under- taken, reliance being mainly on the ordinary sources of information, i. e., trade journals, technical works, and general dictionaries and encyclopedias, and on personal experience and observation. Considering the manner in which it has been pro- duced, no apology need be offered for its obvious defects and shortcomings. The aim has been to com- pile rudimentary information for the young printer, and no attempt has been made to cover the sub- jects exhaustively or to make a cyclopedia of com- plete information. 248580 Tlie Compositor's Stick Methods of Printing PRINTING is the art, act, or process of producing impressions for literary, graphic, or decorative purposes. This may inckide many processes which are not commonly associated with the term, like moulding, coining, stamping, embossing, or the methods used in making calico, wall- paper, decorated pottery, etc., as well as in making photographs. The processes here considered are those wherein ink is applied to the surface from which it is intended to print and transferred by impression to paper, cardboard, or other material. In this sense there are various methods employed, each a separate art, distinct in theory, process, and application. These are known as : The Relief Method, the chief part of which is typography, or printing from types. This includes also wood blocks and metal plates engraved in high relief, like wood-cuts, zinc etchings, and halftone engravings. The Intaglio Method, by which the print- ing is done from polished plates having the lines cut in the surface and filled with ink. Methods of Printing This method includes copperplate and steel- plate engraving, copperplate etching, drj'- point engraving, aquatint engraving, mezzo- tint engraving, and photo-gravure. The Chemical Plane-Surface Method, chief of which is lithography, or printing from stone. This includes also zincography (metal), the several photo-gelatine processes, and the rub- ber offset process. The Relief Method Is that wherein the parts which carry the ink, and thus make the print, stand in relief above the substance out of which they are made, the parts which show white being cut away so that no impression is made on the sheet. Typography, or letter-press printing, is the method of printing from movable types having letters and other characters cast in high relief. The types are independent of each other, but so made that they may be arranged in endless combinations, and after being once used for one line or page may be separated and re-assembled to print other lines or other pages. Other methods require the engraving or preparation of the subject by slow processes which, when once made upon the printing surface, cannot readily be used for anything else. A page of type may be composed, cor- rected, locked up for a pres.s. and impres- sions made from it in an hour's time or less. This may be done with the simplest mate- Methods of Printing vii rials, which may be found in every printing house, however small. The page may also be as readily moulded and the mould it makes used to produce a duplicate printing form in one piece. For the great bulk of book print- ing this duplicate, called an electrotype, is employed. By this method, types sufficient to set up a few pages of this book may be composed, corrected, and the pages moulded, then the type distributed and set again for other pages of the same work, continuing the process for any number of pages. The sur- face of t}'pe forms can also be multiplied by the stereotype process, which is the method now employed for nearly all daily newspapers, as it is the quickest and permits of casting plates in a curved form so that they may be fastened to the cylinders of fast rotar}- print- ing machines. Up to about thirt}- years ago type-setting was done almost entirely by hand work, but since that time type-casting and type-com- posing machines have been developed so skillfully that the greater part of straight- away composition on newspaper, periodical, and book work is now done with machines. (See Type Setting Machine, p. 324, etc.) Closely allied to t)'pography in modern practice are wood engraving, zinc etching, and halftone engraving. Engravings of these kinds are in relief, and when made on blocks which bring their surfaces to the height of type they may be put in the same forms with viii Methods of Printing type, or in separate forms, and printed on an ordinary typographic press. The wood-cut is the older kind of engrav- ing. Because of its slower manipulation and greater cost it has been almost superseded by the zinc plate and the copper halftone. Zinc etching is the process of engraving commonly used for newspapers and for the ordinary grades of periodical and commer- cial work. The copy for reproduction is usu- ally drawn with a pen on white paper or card, with a perfectly black ink, and all the degrees of light and shade must be produced by dots and lines of varj'ing widths and dis- tances apart. Photographs, wash drawings, and fine-grained or tinted pictures must have their essential parts translated into distinct lines and spots in order to be engraved by this method. Halftone engraving is done practically by the same methods as zinc etching, the dif- ference being that, when photographing the design on the metal, a screen is interposed between a sensitive plate in the camera and the copy. The halftone screen varies in fine- ness from 80 to 250 lines to an inch, accord- ing to the coarseness or fineness of the plate required, this being determined by the fin- ish of the paper to be used and the care with which it may be printed. The coarse screen is best suited for the rapid work and cheaper paper of a daily newspaper, while a screen of 135 to 200 lines, on smooth coated papers Methods of Printing ix printed on slow presses, gives finer results in the picture. The finer the screen used, the shallower the plate can be etched, and the smoother the paper and finer the ink must be in order to print clearly. In a wood engraving the lines may be cut sharp and deep, so that it will print clearly on a medium-rough or antique-finish paper. A zinc etching is not usually as deep as a wood-cut and it prints well on a medium- rough paper; if it contains some detail in fine lines it may require smooth paper to show it properly. Relief printing is done on presses of two distinct classes : the platen, or flat surface, and the cylindrical. The original hand-press consisted of a flat bed upon which the type- form was placed ; after being inked and the sheet laid on, the form was subjected to im- pression by another plane surface. The mod- ern platen press embraces the same prin- ciple with the operations applied mechanic- ally instead of by hand labor. The cylinder press is of two classes. One style consists of a flat bed holding the printing form, which passes back and forth beneath a revolving cylinder carrying the sheet and giving the impression. The other consists of two fac- ing cylinders, to one of which a curved printing form is attached the other, having ; a smooth surface, imparts the impression to the sheet as it passes between the two cylinders revolving in opposite directions. Methods of Printing This latter style of press is the kind em- ployed for daily newspapers, large-edition periodicals, and advertising matter issued in large quantities. The flat-bed-and-cylinder style of machine is the kind in most com- mon use. It is made in many varieties by different manufacturers, and is the kind up- on which the largest part and the best grades of typographic printing is done. The me- chanical platen press is used for jobbing and miscellaneous small work, while the hand-press is largely employed for taking proofs of type and engravings, and for work of which only few copies are required. The Intaglio Method By this process the design is cut in the sur- face of the plate, the lines or dots thus en- graved being filled with ink, the face of the plate then wiped clean, and the paper, slight- ly damp, pressed on the plate under the cyl- inder of a rolling press.