The Art of Photoengraving (1943) 🇺🇸
How illustrations are rendered into metal for printing — fourth of a series.
Photoengraving may be described as a method of transforming pictures into metal for printing. By means of the art, a picture first is taken, the negative is transferred to a sensitized metal plate, and into this plate is etched a likeness of the subject in such a manner that it may be transferred to paper.
The extent to which a knowledge of photoengraving processes is valuable in the management of a theatre depends upon the practices of the theatre. Many smaller houses dispense with illustrations altogether in their newspaper advertising. Others use stereotype mats or ready-made cuts supplied by the distributor or an advertising service.
Photoengravings are divided into two principal divisions: halftones and line etchings. The processes are much the same, except with respect to photographing and frequently the material of which the plate is made. Whether one or the other is to be used is generally indicated by the nature of the copy. A photograph of a landscape, for example, would be reproduced by the halftone process because of its general opacity and variation in tone. A pen and ink drawing of the same landscape could be reproduced as line etchings, only the lines being made by the pen being desired.
In order to make a true likeness of the photograph to be reproduced, with all its varying degrees of darkness and lightness, the subject is photographed by the engraver through a screen. The effect on the negative is that of a vast number of dots, varying in intensity according to the tones of the original photograph. It is these dots that print and effect a reproduction of the subject on paper.
In line etchings no variation in tone is possible without a special process (except to the extent that the copy may have a smaller or greater number of lines or dots concentrated in certain areas.) The subject is not photographed through a screen, but directly, and the plate prints merely black (or whatever colored ink is used) and white. There are no tones. Any portion of the copy that is not dark enough to make an impression on the photographic plate (negative) is totally lost to the finished engraving.
In reference to line etchings, it was stated that variations in tone could not be obtained in this type of reproduction without employing a special process. That special process is called Ben Day, after the man who invented it. Briefly, this process consists in transferring to the entire negative, or to any portion of it, an effect of a screen, stripes, weaves or any of many patterns.
This does not mean, however, that the tonal qualities of a photograph could thus be achieved. Without use of a halftone screen these would be entirely lost or transformed into black. The Ben Day process (except in special cases that need not be touched on here) is used to add interest to line drawings by filling certain white areas, or lightening certain dark areas.
As such, Ben Day is extensively employed today in the making of line etchings, especially for advertising. It permits the “painting in” of interesting backgrounds without the services of an artist. It is even being used today for the making of color plates from pen or pencil subjects.
Halftones as well as line etchings sometimes lend themselves to special mechanical processing for effect. One usually sees halftones square or rectangular, and probably there are relatively few occasions when they would be as pleasing otherwise. Sometimes, however, the subject suggests emphasis on certain elements, or the layout may indicate variation from the usual shape.
Possible treatments in such cases is a circular or oval shape, an outline and a vignette. The first two are self-explanatory. By an outline halftone is meant one in which the background is cut away from certain elements of the subject; everything except a small portion of the area on which a figure is standing is sometimes so removed, or the spire of a building is so outlined that its only “background” is the paper itself when the engraving is printed. This effect is achieved merely by tooling around the element and routing out the unwanted metal.
A vignette is obtained in the acid-etching stage of the process. By controlling the effect of the acid on the plate through the use of acid-resistant material, the dot formation shades off gradually toward the edges of the engraving, and when printed, the reproduction seems to blend into- the tone of the paper.
As we noted above, halftones make their impression in printing by means of tiny dots, the variation of which effects the tones of the subject. The screen through which the subject or copy is photographed in order to render, the dot formation upon the negative, is selected according to the nature of the paper upon which the engraving is to be printed. Very soft paper of loose texture spreads ink, and consequently it requires a very sparse dot formation — that is, a very course screen. If the proper screen has 55 lines to the inch, it is designated a 55-line screen. There are screens for almost any practical density, as high as 175 lines to the inch. The latter could be used for only the hardest coated paper. A halftone made with a fine screen and printed on soft paper would look smudgy, while one of course screen and printed on hard enamel paper would be obscured by conspicuous dots. These considerations are of significance in theatre advertising chiefly with respect to announcements, programs, etc., when the person in charge of advertising might have to select the paper. Newspapers and periodicals have a fixed grade of screen.
Copy Clarity and Tone
It should always be remembered that the better the copy, the better the result which the engraver can get. Engraver’s copy should be carefully examined before it is submitted. Sometimes a drawing that appears all right comes up as a halftone or line etching quite different from the effect intended. One should remember first of all that engraver’s copy has to be photographed.
Because photography is fundamentally involved, attention should be given the shades of any copy done in color but not intended for process color printing. In halftone reproduction, even a light yellow will come up darker than a fairly dark blue or violet. Red is always a decided black, and even green reproduces dark. Photographs in sepia, even when to the eye there seems to be contrast, comes up very dull. To some extent the engraver can filter out obtrusive shades, but it is better to have the copy in the blacks and whites and grays.
Precise stipulation of dimensions wanted is naturally very important. In lieu of a layout in scale, the width or height need only be stated, with the portion of the copy to be reproduced indicated on the face (with a china marking pencil if a glossy print) or on the back. When both the height and the width must be of certain exact dimensions, both dimensions must be given.
It is almost always better to reduce the copy in the engraving than to enlarge it. A small amount of the brilliance of halftone copy is lost in the photographic process, and spreading the tones in enlarging tends further to dull the effect. — George Schutz.
Source: Motion Picture Herald, October 1943