Engraving. On Wood. The Block.—The best wood fnr the purposes of the engraver is box (see Timber), whether English, American, or Levantine ; it should be light straw-yellow in colour, and free from black or white spots and red streaks, which indicate a soft wood. Small wood is generally pretty free from blemishes. The supply of good box-wnod is by no means plentiful, and several other kinds of wood have been proposed or adopted as substitutes, the principal being sycamore and pear (much used for large coarse cuts, but too soft and irregular for fine work), piacha, persimmon, and American dog-wood ; all these are described in the article on Timber. A sub stance deserving careful trial for this purpose is celluloid (see pp. 610-8), which might be obtained in sheets of any desired size. When wnod is used, a large cut often necessitates the bolting together of several small ones. Wend blocks are about 1 in. high, and are then planed down to the exact height of type, and hrought to a very smooth surface. They require keeping fur some months to become seasoned.
Drawing on the Block.—Before any drawing can be made on the polished surface of the block, the latter must receive a slight wash. This is made with water and Chinese white, or very fine Bath-brick dust, nr the scrapings of glazed cardboard ; it is gently rubbed off when dry, leaving a surface on which the pencil will take. A tracing of the outline of the subject is made, and placed nn the block with a piece of transfer-paper between, remembering that the picture will be reversed in printing. Every line is gone nver with a sharp point. The outlines are then corrected and completed by a sharp-pointed HHHH pencil, the tints being afterwards filled in by a softer pencil, or thin washes of Indian-ink, to show the effects of light and shade. All washes must be used with such care as not to affect the wood by their moisture. The portions nf the block not under immediate operation are kept covered with smooth, blue, glazed paper, to preserve them from injury, and reduce the glare from the lamp.
Proofing.—When the drawing is finished, a proof may be taken in the following manner, before blocking out the cut, that is, before the superfluous wood is cleared away :—Rub down a little printing-ink on a slab till it is fine and smooth ; take some of this on a silk dabber, and carefully. dab the block until sufficient ink is left upon the surface, without allowing any to sink below it. Lay a piece of India paper on the block, with abnut 2 in. margin all round ; on this, place a thin smooth card ; rub this over with the burnisher, taking care not to shift the card or paper.
The Lamp.—A clear and steady light, directed immediately upon the block to be cut, is a most important pnint, and in working by lamplight, it is necessary to protect the eyes from the heat and glare. The lamp shown at A, Fig. 1168, can be raised or lowered at pleasure, by sliding the bracket
up or down the standard, it being fixed in the desired position by means of the small set-screw. A large globe of transparent glass, filled with clean water, placed between the lamp and the block, causes the light to fall directly upon the latter. The dotted line shows the direction of the light ; by lowering the lamp, this light would take a more horizontal direction, thus enabling the engraver to work farther from the lamp. A shade over the eyes is occasionally used as a protection from the light of the lamp.
The Tools.—The tools consist of gravers, tint-tools, gouges or scoopers, flat-tools or chisels, and a sharp-edged scraper, something like a copper-plate engraver's burnisher, which is used for lowering the block. Of each of these tools, several sizes are required.
The " outline-tool," B, Fig. 1168, is chiefly used for separating one figure from another, and for outlines : a is the beak of the tool ; b, the faee ; c, the point ; d is technically termed the belly. The horizontal line 1-2 shows the surface of the block. All the handles when received from the turner are oircular, but as soon as the tool has been inserted, a segment is cut away from the lower part, so that the tool may clear the block. The blade should be very fine at the point, so that tho lino it outs may not be visible when the block is printed, its chief duty being to form a termination to a number of lines running in another direction. Although the puint should be fine, the blade must not be too thin, for it would then only make a small opening, which would probably close up when the blook was put in the press. When the tool becomes too thin nt the point, the lower part must be rubbed on a hone to enable it to out out the wood instead of sinking into it. Nine " gravers " of different sizes, starting from the outline-tool, are sufficient for ordinary work. The blades as made are very similar to those used in copper-plate engraving ; the necessary shape for wood engraving is obtained by rubbing the points on a Turkey stone. The faces, and part of the backs, of nine gravers are shown at C, Fig. 1168 ; the dotted line a-c shows the extent to which the tool is sometimes ground down to broaden the poiut. This grinding rounds the point of the tool, instead of leaving it straight, as shown at a-b. Except for the parallel lines, called " tints," these gravers are used for nearly all kinds of work. The width of the line cut out is regulated by the thickness of the graver near tho point, and the pressure of the engraver's hand.