Two innovations ended the printing trade-off: the introduction of the rotary press and wood engraving.
The first rotary presses for relief letterpress printing were invented in the 1820′s. (Before the nineteenth century, printing presses worked by exerting downward pressure on the paper and the inked type, and were relatively slow.) Rotary presses allowed newspapers and books to be produced with greater speed and sharper detail than they could be on vertical presses. The woodcut illustrations then available lagged behind the quality of the letterpress, and metal etching and engraving plates could not print on rotary presses then available. But around this time an English clergyman-naturalist-artist named Thomas Bewick (pronounced “Buick”) had a brilliant idea: He used engraving gouges to cut images into the end-grain of a hardwood block. The end-grain is at right angles to the side-grain, and is in effect like no grain at all. (Imagine holding a hairbrush bristles-up: the closely-packed ends of the bristles are like the end-grain of wood, and it is easy to run the tip of your finger over them freely in any direction; in the same way, it is easy for an engraving gouge to cut smoothly in any direction on the surface of an end-grain wood block.)
Bewick’s invention of wood engraving allowed artists to produce finely detailed prints on wood blocks; if the blocks were “type-high” (the same thickness as the height of the type in a printing press bed) they could be locked in the press bed with the type and printed alongside it. This allowed finely detailed illustrations to be printed within a page of type for the first time. When wood engravings and type were combined in rotary printing presses, high-quality but inexpensive illustrated publications became a reality.
Later on, wood engravings made it possible to reproduce photographs in publications for the first time. The engraving block was covered with photosensitive emulsion, exposed to light under a glass photo negative, and the positive photo image developed and fixed on the block surface like a photograph on paper. The wood engraver would then engrave away all the white portions of the photographic image, carve variably spaced dots and lines to reproduce several shades of gray, and leave areas of solid black mostly untouched. This became the standard method of producing photographic images in print until the widespread use of the mechanical photoengraving process and the halftone screen in the 1890′s.
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