46. Revarnishing with the Brush.—Instead of revarnishing with the dabber, the ground may also be laid with the brush. For this purpose you can use the stopping-out varnish mixed with lamp-black. Spread a coat of varnish all over the plate, using a very soft brush; if the copper should not be perfectly covered on the edges of the deeply etched lines, add a second coat of varnish. Do not wait till the varnish has become too dry before you execute the retouches, which, of course, must also be bitten in as usual. Mixed with lamp-black, the stopping-out varnish allows even the finest lines to be seen, which would not show as well if the varnish were used in its natural state. Many engravers use this varnish instead of the transparent ground.
47. Partial Retouches.—Patching.—For partial retouches and for patching the stopping-out varnish is also used, but in a simpler and more expeditious way. Cover the part in question with a tolerably thick coat of varnish, and when you have finished your retouch, slightly moisten the lines with saliva, to prevent the few drops of acid which you supply from your bath with the brush from running beyond the spot on which they are to act. If pure acid is used,—which is still more expeditious,—the effervescence is stopped by dabbing with a piece of blotting-paper, and the operation is repeated as long as the biting does not appear to be sufficient. For very delicate corrections it is advisable not to wait until the first ebullition is over; but it must be left to the feeling to indicate the most opportune moment for the application of the blotting-paper. If you proceed rapidly and cautiously, you can obtain extremely fine lines in this way, as you have had occasion to see under other circumstances (see paragraph 40, p. [25]).
You may recollect that I spoke of lines which had not bitten: I alluded to this spot in the middle of the bridge (see [Pl. Ia]). You did not bear on your needle sufficiently, and hence it did not penetrate clear down to the copper; consequently, after having compared the proof of the first state with the original ([Pl. II.]), you must do the necessary patching according to the instructions just given to you.
48. Dry Point.—Whenever it is necessary to retouch, or to add to very delicate parts of the plate, such as the extreme distance, or any other part very lightly bitten, it is safer to use the dry point, as in such cases retouching by acid is a most difficult thing to do. The tone must be hit exactly, and without exaggeration.
Your plate offers an opportunity for the use of the dry point: the sky and the mountain are partly etched; you can improve them by a few touches of the dry point.
The dry point is held in a perpendicular position, and is used on the bare copper. It must be ground with a cutting edge, and very sharp, so that it may freely penetrate into the copper, and not merely scratch it. You cut the line yourself, regulating its depth by the amount of pressure used, and according to the tone of the particular passage on which you are working. For patching, it is more frequently used in delicate passages than in others, as, even with great pressure, the strength of a dry point line will always be below that of a line deeply bitten. In printing, the dry point line has less depth of color than the bitten line, as the acid bites into the copper perpendicularly at right angles; while the furrow produced by the dry point, which offers only acute angles, takes up less ink, although it appears equally broad. This inequality disappears if a plate in which etched lines and dry point work are intermingled is re-bitten; the difference in tone is then equalized.
On the other hand, the difference in the appearance of etched lines and dry point work produces curious effects. Thus, if a passage which is too strong and appears to stand out is to be corrected, a few touches of the dry point will be sufficient to soften it, and to push it back to another distance.
The dry point is not only used for retouching; it is sometimes employed, without any etching, to put in the whole background.
49. Use of the Scraper for removing the Bur thrown up by the Dry Point.—The dry point work being finished, the bur thrown up by the instrument must be removed. The bur is the ridge raised on the edge of the line, as the point ploughs through the metal; you can satisfy yourself of its existence by the touch. In printing, the ink catches in this ridge, and produces blots. The bur is removed by means of the scraper, an instrument with a triangular blade, one of the sides of which, held flat, is passed over the plate in the opposite direction to that of the stroke of the point, and so as to take the line obliquely. You need not feel any anxiety about injuring the plate; the touch will tell you when the bur has disappeared. In the case of dry point lines crossing one another, each set running in a different direction must be drawn as well as scraped separately, in the manner just described; otherwise you will run the risk of closing the lines which cross the path of the scraper, by turning the bur down into the furrows.
50. Reducing Over-bitten Passages.—So much for the additions. We will now pass on to the very opposite: the shadow thrown by the parapet, and the ground between the man and the woman, have been over-bitten. These parts do not harmonize with the neighboring parts, and are stronger in tone than the corresponding parts of the original.