[Half-tone processes] are practised in much the same way as the albumen and bitumen line methods already described, in so far as that they are worked with acids and upon zinc or copper. At first these half-tone blocks were made in zinc, but recently some reproductive firms have preferred to use copper. Messrs. Waterlow and Sons, in this country, generally employ copper for half-tone blocks from drawings or photographs. Copper prints a softer and more sympathetic line, and does not accumulate dirt so readily as zinc. All the half-tone blocks in this volume are in copper. By these processes the photographs that one sees reproduced direct from nature appear in print without the aid of the artist. They are often referred to as the Meisenbach process, because the Meisenbach Company was amongst the first to use these methods in this country. The essential difference in their working is that there is a ruled screen of glass interposed between the drawing or object to be photographed and the negative. Generally a screen of glass is closely ruled with lines crossing at right angles, and etched with hydrofluoric acid. Into the grooves thus produced, printing-ink is rubbed. The result is a close network of black lines upon glass. This screen, interposed between the sensitized plate in the camera and the object to be photographed, produces upon the negative the criss-cross appearance we see in the ultimate picture. In the half-tone reproductions by Angerer and Göschl, of Vienna, this appearance is singularly varied. The screen used by them is said to be made from white silk of the gauziest description, hung before a wall covered with black velvet in such a manner that the blackness of the velvet can be seen and photographed through the silken film. A negative is made, and from it a positive is produced, which exhibits a curiously varied arrangement of dots and meshes. The positive is used in the same way as the ruled-glass screens.
6¾ × 6¼. PENCIL AND PEN AND INK DRAWING REPRODUCED
BY HALF-TONE PROCESS.
The network characteristic of half-tone relief blocks can be made fine, or medium, or coarse, as required. The fine-grained blocks are used for careful book and magazine printing, and the medium-grained for printing in the better illustrated weeklies; the coarse-grained are used for rougher printing, but still are nearly always too fine for newspaper work. The Daily Graphic, however, has solved the problem of printing them sufficiently well for the picture to be discerned. Beyond this the rotary steam-printing press has not yet advanced.
In appearance somewhat similar to a half-tone block, but with the tint differently applied, is the illustration of [The Village Street, Tintern: Night]. Here is a pure pen-drawing, scratched and scribbled to blackness without much care for finesse, the great reduction and the tint being reckoned upon to assuage all angularities. The original drawing was then lightly scribbled over with blue pencil to indicate to the process-man that a mechanical tint was required to be applied upon the block, and word was specially sent that the tint was to be squarely cut, not vignetted. The result seems happy. This is a line block, not tone.