The shade must be between the plate and the light, in order to be able to see the marks of the burnisher; fine charcoal and oil will remove these marks, and the oil-rubber will clear away the charcoal marks. The charcoal can be obtained at a coppersmith's or plate-printer's. If a burnisher is good at first, it never requires alteration. The scraper must be occasionally sharpened.
Take half a ball of hard ground, mixed as described under the head Etching Ground; to that add a piece of mutton suet. Melt them well together, observing that the ingredients must be thoroughly incorporated; then pour into cold water, and use it as before directed.
The process is exactly the same as in laying the etching ground, with this difference, that the plate does not require so great a heat. Smoke the plate the same as in laying etching ground. The ground must be spread as thinly as possible, to cover the plate and bear smoking. The surface of the plate must be alike all over, and quite bright or shining. If any part but the edges appears sooty, it must be cleared off, and the plate polished, as described for etching, and laid again. A good ground may be made at the first melting, but that can scarcely be expected. It may be as well to test the quality of the mixture before laying a whole ground. To this end, heat a small portion of the plate; lay on the ground; smoke it; and let it get quite cold. Obtain some of the finest tissue paper, of very even texture; Place a piece of the paper on the patch of ground laid, and, with a fine-pointed H pencil, make a slight sketch - a bit of foliage, for instance; the paper should slightly stick to the plate; when carefully raised by the two bottom corners, the back of it should clearly show every line made on its surface, only darker. Should the sketch on the copper look as if it was dotted all over, the mixture of ground will do.
Should the ground adhere to the paper, like marks with pen and ink, the ground must be melted, with an addition of hard ground; and if even the softest marks of the pencil do not pull the ground from the plate, the ground must be remelted and remixed until it is fit for work. As the temperature has great effect on this ground, that which will answer for summer will not do for winter, so it may be as well to make two or three mixtures, and number them according to their several degrees of hardness. Having succeeded in mixing the ground, take a piece of tissue paper twice the size of the plate. Place the plate in the centre, and with a black-lead pencil draw a line all round it. Make the same mark on the other side; then lay the ground as described. When cold, wipe the back and edges before taking off the hand-vice. This ground being very tender, care must be taken not to touch the face of the plate.
The drawing is to be made upon the square marked on the paper. If it is intended to copy a subject, the same process as in transferring for the hard-ground etching is used; only, instead of transferring the red lines on to the plate, they must be made within the square marked on the paper. Take care that the tracing is reversed. If it is intended to draw on the plate without copy, lightly make the design on the square marked with fine-pointed red chalk. Should the subject be figures, everything must be drawn to the left hand, or reversed. Fold a silk handkerchief in four; lay it fiat and smooth on the table; place on it the paper, with the chalk sketch downwards. Then, with great care, lay the plate, face down, exactly on the square mark of the paper; fold over the back the surplus paper, and fix the sides with four thin spots of sealing wax near the corners; be sure not to move the plate on the silk. Take up the plate carefully, and place it for work. Use a hand-rest, as in etching, and a hard-pencil, H H, on the places you wish to be. dark. In soft-ground engraving, the drawing must be finished the day it is commenced; the mechanical part of the work may be delayed. When the drawing is finished, pull np the paper by the two bottom corners.
Varnish the border down the same as in etching. The acid used must be much stronger; the border wax higher and broader in the spout, as you may perhaps have to pour oft' suddenly.
In biting-in, pour off the acid when the ground begins to break up; that is, coming up in patches. During the biting-in, the soft camel-hair pencil may be used, but very tenderly. Wash well oft with cold water, and place the plate to dry. For cleaning, see Etching. Should the plate require more finishing, have recourse to the hard ground without smoking.
This was formerly resorted to where the object was to produce a plate, the impressions from which were to be coloured. It is recognised by its similarity to Indian ink or sepia drawing; for, in working the plate at press, black and brown inks are used indifferently, as the artist or publisher may direct. Rosin forms the ground in this method of engraving.
Break some of the best white rosin into pieces, put into a bottle with spirits of wine, and shake occasionally until the rosin is dissolved. The bottles must have corks, not glass stoppers. Have two other bottles ready; mark the bottles 1, 2, 3. No. 1 is the bottle in which the rosin is placed. Pour a third of No. 1 into No. 2, and nearly fill it with spirits of wine. Pour into No. 3 rather less of the mixture from No. 1, and nearly fill it with spirits of wine. These bottles must be occasionally shaken, and their contents allowed to settle well before use. The contents of the three bottles must be so mixed that they are one under the other in strength, as the size of the grain to be laid on the plate depends on the quantity of rosin each mixture contains. The more rosin the larger the grain. The spirits should be entirely free from water.