The pnrallel lines forming an even and uniform tint, as in the representation of a clear sky, are obtained by what is called the " tint-tool," which is thinner at the back, but deeper at the side, than the graver, and the angle of the facie at the point is much more acute, as shown at D, Fig. 1168 : a is a side view of the blade ; b shows the faces of nine tint-tools of varying fineness. The handle is of the same form as that used for the graver. The graver should not be used in place of the tint tool, as, from the greater width of its point, a very Blight inclination of the hand will cause a per ceptible irregularity in the distance of the lines, besides tending to undercut the line left, which must bo carefully avoided. E, Fig. 1168, shows the points and faces of the two tools, from a comparison of which, this statement will be readily understood. As the width of the tint-tool at b is little more than at a, it causes only a very slight difference in the distances of the lines cut, if inclined to the right or the left, as compared with the use of the graver. Tint-tools that are strong in the back are to he preferred, as less likely to bend, and giving greater freedom of execution than weak ones. A tint-tool that is thicker at the back than at the lower part, leaves the black raised lines solid at their base, as at F, Fig. 1168, the block being less liable to damage than in the case of G, Fig. 1168, in which the lines are no thicker at their base than at the surface. The face of both gravers and tint-tools should be kept long rather than short ; though if the point be ground too fine, it will be very liable to break. When, as at H, Fig. 1168, the face is long,—or, strictly speaking, when the angle formed hy the plane of the face and the lower line of the blade is comparatively acute,—a line is cut with much greater clearness than when the face is comparatively obtuse, and the small shaving cut out turns gently over towards the hand. When, however, the face of the tool approaches to the shape seen at J, Fig. 1168, the reverse happens ; the small shaving is ploughed out rather than cleanly cut out, and the force necessary to push the tool forward frequently causes small pieces to fly out at each side of the hollowed line, more especially if the wood is dry. The shaving, also, instead of turning aside over the face of the tool, turns over before the point, and hinders the engraver from seeing that part of the pencilled line which is directly under it. A short faced tool of itself prevents the engraver from distinctly seeing the point. When the face of a tool has become obtuse, it ought to he ground to a proper form ; for instance, from the shape of the figure K to that of L, Fig. 1168.
Gravers and tint-tools, when first received from the makers, are generally too hard—a defect that is soon discovered by the point breaking off short as soon as it enters the wood. To remedy this, the blade of the tool must be tempered to a straw-colour, and either dipped in sweet oil, or allowed to cool gradually. If removed from the iron while it is still straw-coloured, it will have been softened no more than sufficient ; hut should it have acquired a purple tint, it will have been softened too much, and instead of breaking at the point, as before, it will bend. A small grindstone is of great service in grinding down the faces of tools that have become obtuse. A Turkey stone is a very good substitute, as, besides reducing the face, the tool receives a point at the same time ; but this requires more time. Some engravers use only a Turkey stone for sharpening their tools ; a hone in addition is of great service. A graver that has received a final polish on a hone cuts a
clearer line than one which has only been sharpened on a Turkey stone ; it also cuts more pleasantly, gliding smoothly through the wood, if it be of good quality, without stirring a particle on either side of the line. The gravers and tint-tools used for engraving on a plane surface are straight at the point, as represented at M, Fig. 1168 ; but for engraving on a block rendered concave in certain parts by lowering, it is necessary that the point should incline slightly upwards, as at N, Fig. 1168. The dotted line shows the direction of the point used for plane-surface engraving. There is no difficulty in getting a tool to descend on one side of a part hollowed out or lowered ; but unless the point is slightly inclined upwards, as shown, it is extremely difficult to inake it ascend on the opposite side, without getting too much hold, and thus producing a wider white line than intended.
Gouges 0, Fig. 1168, of different sizes are used for scooping out the wood towards the centre of the block ; whilst flat tools, or chisels, are chiefly employed in cutting away the wood towards the edges, about fi in. below the subject. The gouge is similar to an ordinary carpenter's gouge, except that it is solid, being a round bar, with the end ground off at an angle. The other articles required are a sand-bag, on which to rest the block whilst engraving it ; an agate burnisher and a dabber, which are used for taking proof-impressions of the woodcut ; an oil-stone, and eye-glass with shade.
Holding the Graver.—Engravers on copper and steel, who have much harder substances than wood to cut, hold the graver with the forefinger extended on the blade beyond the thumb, as at P, so that by its pressure the point may be pressed into the plate. As boxwood, however, is much softer than these materials, and as it is seldom of perfectly equal hardness throughout, it is neces sary to employ the thumb at once as a stay or rest for the blade, and as a check upon the force exerted by the palm of the hand, the motion being chiefly guided hy the forefinger, as shown at Q, Fig. 1168. The thumb, with the end resting against the side of the block, in the manner repre sented, allows the blade to move backwards and forwards with a slight degree of pressure against it, and in case of a slip, it is ever ready to check the graver's progress. This mode of resting the thumb against the edge of the block is, however, only applicable when the cuts are so small as to allow the graver, when thus guided and controlled, to reach every part of the subject. When the cut is too large to admit of this, the thumb rests upon the surface of the block, as at R, Fig. 1168, still forming a stay to the blade of the graver, and checking at once any accidental slip.
Plugging.—If a slip or mistake occurs in a woodcut, it may he remedied hy the insertion of a plug into a hole drilled in the block. If the error is a small one, the hole need not be deep ; but if a large piece has to he inserted, it must be deeper in proportion. A plug is cut, of a round, taper shape ; the small end is inserted in the hole, and the plug is driven down, without, however, using too much force. The top of the plug must then be cut off, and carefully brought to LI. smooth surface, level witli the rest of the block ; if this is not done, the ping will be visible on the print. If the error to be remedied happens to be in a long line, a hole must be drilled at each end, and the wood between the two holes removed by small chisels, the hollow space being filled up in a similar way to that described.