A third style of engraving in relief, the "early dot manner," was practised for some time during the period of the Incunabuli, when the art was, as the root of this Latin word shows, still "in its cradle." By this method the work was no longer carried out on wood, but on metal; and the engraver, instead of completely hollowing out those parts destined to print light, merely pitted them with minute holes, leaving their bulk in relief. He was content that these masses should appear upon the paper black, relieved only by the sprinkling of white dots resulting from the hollows.
We just mention by way of note the process which produced those rare specimens called "_empreintes en pâte_." All specimens of this work are anterior in date to the sixteenth century, and belong less strictly to art than to industry, as the process only consisted in producing on paper embossed designs strongly suggesting the appearance of ornaments in embroidery or tapestry. To produce these inevitably coarse figures a sort of half-liquid, blackish gum or paste was introduced into the hollow portions of the block before printing. On the block thus prepared was placed a sheet of paper, previously stained orange, red, or light yellow, and the paste contained in the hollow places, when lodged on the paper, became a kind of drawing in relief, something like an impasto of dark colour. This was sometimes powdered with a fluffy or metallic dust before the paste had time to harden.
Though simple enough as regards the mere process, in practice line engraving demands a peculiar dexterity. When the outlines of the drawing that is to be copied have been traced and transferred to a plate usually made of copper,[1] the metal is attacked with a sharp tool, called the dry-point. Then the trenches thus marked out are deepened, or fresh ones are made with the graver, which, owing to its shape, produces an angular incision. The appearance of every object represented in the original must be reproduced solely by these incised lines: at different distances apart, or tending in various directions: or by dots and cross-hatchings.
Line engraving possesses no other resources. Moreover, in addition to the difficulties resulting from the use of a refractory tool, we must mention the unavoidable slowness of the work, and the frequent impossibility of correcting faults without having recourse to such drastic remedies as obtaining a fresh surface by re-levelling the plate where the mistakes have been made.