After being prepared in the above man ner, the ground is tied in a piece of lust ring for use, and another piece of the same kind of silk must be made into a dabber by tying a quantity of cotton in it. The copper-plate, hammered to a con siderable degree of hardness, polished as if intended for the graver, and perfectly cleansed with whiting, is then secured at one corner by a hand vice, heated over a charcoal fire, and the silk containing the ground rubbed over it, till every part is covered by the melted composition ; but before it cools the silk dabber must be ap plied in all directions, till the surface of the plate is thinly and equally varnished. After this part of the process is complet ed, several lengths of wax taper, twisted together, are to be lighted, the plate rais cd by the vice in the left hand, and the right, holding the burning taper,iis to be moved gently backwards and forwards under the ground, carefully avoiding touching it with the wick, yet causing the flame to spread over the surface, which will render it perfectly black, smooth, and shining, in a short time ; this is to be ascertained by turning the plate : If the copper appears through the ground, the taper must be applied again imme diately ; but if it is held too long beneath the plate, the ground will become opaque, and break when the aqua fortis is used.
The next object is, to transfer the de sign to the ground, which may be done by drawing it on thin white paper with a black-lead pencil, and having it passed through the copper-plate printer's rolling press, who will accomplish it by laying the plate carefully on the board of his press, the pencilled paper slightly damp ed on it, and turning the press, the lead will be conveyed firmly to the ground, which will appear in perfect outlines on removing the paper. Another method is, to draw the design reversed from the original; rub the back with powdered white chalk, and layin it on the ground, trace the lines through with a blunt point: this operation requires much precaution, or the point will cut the ground; besides, if the paper is not securely fastened with wax at the corners, it may slip, and either interrupt the true continuation of the lines, or scratch the ground.
In working with the etching needle nothing more is required than to keep it upright, that the lines made by it through the ground may not slope, and thus make the aqua fortis corrode improperly ; but it should be particularly observed, that the point, though taper, must be so round ed as to be free from a possibility of its tearing the surface of the copper, which would prevent the progress of the point, and ruin the plate when bitten ; the ne cessary polish of the point may be ac complished by rubbing it on the sole of is shoe. The young artist must now be left to his own exertions, as directions for etching beyond those already given are useless, and he will acquire more knowledge and freedom from copying good prints in one week than a quarto volume of observations would afford. It seems almost needless to add, that every line must be kept distinct, at all events, throughout the plate, and that the most distant should be closer and more regular than those in the fore ground, as the greater the depth of shade the broader and deeper must the lines be made.
When the etching of the plate is com pletely finished, the edges of it must be surrounded by a high border of wax, so well secured that water will not penetrate between the plate and if. The best spirits of nitre fortismust then be diluted with water, in the proportion of one part of the former to four of the latter, which will be found to answer the first opera tions, if the weather is fine and the atmo sphere free from moisture ; but if the contrary is the case, the spirits of nitre must be increased in proportion to the humidity of the air ; this, when poured on the plate, cannot be too attentively observed, in order to remove the bubbles of fixed air with a feather, and to ascer tain the time for stopping out the lightest parts ; for it must be remembered, the whole secret of biting or corroding any subject consists in the judicious manner in which the depth and breadth of the lines are varied, as by proper manage ment they may be left scarcely percepti ble, or increased very considerably. The composition used for the above purpose is turpentine varnish mixed with lamp black, and diluted so as to be used freely with a camel's hair pencil; this, applied to the parts of the plate sufficiently cor roded, will effectually prevent the aqua fortis from touching it again, and the re mainder proceeds as if no such application had taken place : it will be necessary to strengthen the water as the work be comes nearer completion, but cautiously, lest the ground should be broken ; and every time the aqua fortis is removed, the pltate must be washed with clean water, andgradually dried, otherwise the varnish cannot be used, and the lines would be clogged with the decomposed metal. For taking the ground from the plate it is usual to cover the surface with olive oil, and heating it, wipe the plate with a soft piece of old linen and spirits of turpen tine, will effectually remove all remain ing dirt.
Re•biting, is the art of strengthening those lines of an etching, in a plate from which the original ground has been cleans ed. This is done by applying the ground as at first directed, but with great care, that the melted composition does not fill, or even partially fill the lines, to prevent which the cotton wrapt in silk, called the dabber, should be used exclusively, by taking a small quantity of melted ground on it, and gently touching the parts be tween the lines, till they are equally and completely covered; if the plate is con siderably heated, the ground will spread with more facility over the various inter rupted surfaces. Carelessness or inatten tion will instantly ruin this process, and the whole of the plate : a border of wax must surround the parts to be re-bitten, and a channel made to carry off the aqua fortis without injuring those already com pleted. Supposing the operations of etch ing and biting the plate entirely finished, nothing more remains than to examine it attentively, and improve it with the graver and dry point.