The most it can do in this direction is to indicate, it cannot express; it can exhibit strong contrasts and delicate gradations of light and shadow, and it can suggest varying intensity of hues, by the greater or less depth of its blacks and grays; but real color and perfect chiaroscuro it relinquishes to painting. Form, therefore, is left as the main object of the wood-engraver’s craft, and the representation of form is effected by delineation, drawing, line-work. This is why the great draughtsmen, such as Dürer and Holbein, succeeded in designing for wood-engraving. They knew how to express form by lines, and they did not attempt to do more even when suggesting color-values by the convention of black and gray. Line-work is thus the main business of the engraver, because form must be expressed by lines. Line-work, however, is of different kinds, and all kinds are not equally proper for the art. Hitherto the fineness of line by which copperplate-engraving easily obtains delicacy of contour and soft transitions of tone, has been rarely and with difficulty attained by the best-skilled hand and eye among wood-engravers, and when attained has, usually, not been successfully printed. There remains, however, no longer any reason to exclude fine lines from wood-engraving, when once it has become plain that such work is possible without a wasteful expenditure of labor, that its results are valuable, and that it can be properly printed. But if it shall prove that the character of the line proper to copperplate is also proper to wood, it may be looked on as certain that the line-arrangement proper to the former material can never be rationally used for the latter. The crossing of lines to which the engraver on copperplate resorts is especially laborious to the engraver in wood, and after all his toil does not give any desirable effect which would not have resulted from other methods of work. It has been seen that Dürer employed this cross-hatching in imitation of copperplate-engraving; but he did so because he was ignorant of the way to arrange color so that this difficult task of engraving cross-hatchings would be unnecessary. Holbein, who was equally ignorant of the possibilities of white line, rejected cross-hatching. Bewick also rejected it, and proved it was unnecessary even where much color was to be given. In the later work of the sixteenth century, and in modern English work, wood-engraving imitated its rival art both in the character and the arrangement of its lines; it failed in both instances mainly because such imitation involved a waste of labor, and did not result in works so valuable artistically as were obtained by copperplate-engraving with far greater ease. At present the objection to the use of cross-hatching in wood-engraving is as serious as ever, but the employment of fine lines for some purposes, as in the rendering of delicate textures and tones, has been justified, mainly in consequence of innovations in the modes of printing.