ETCHING, a method of engraving on copper, in which the lines or strokes, instead of being cut with a tool or graver, are eaten in with aquafortis. See Engraving.

Etching, though not very modern, is of later invention than engraving with the tool, of which it was at first only an imitation, practised by painters and other artists, as they could much sooner form their hands to, and attain a facility of, working in this way than with the grayer. But being nevertheless considered as a counterfeit kind of engraving, and therefore inferior to the other, it was cultivated in a very confined manner; the closeness of the resemblance of the work to that performed by the tool being made the test of its merit, and consequently the principal object of aim in those who pursued it. This servile restriction of the art of etching to the imitation of the original kind of engraving was a great cause of retarding its advancement towards perfection, as many of the most able masters cramped their talents by the observ[7:9:373]ance of so narrow a rule. This may be seen in the instances of Sadelcrs, Swaneberg, Villamena, and particularly Le Bosse, who, in his treatise on engraving, has laid it down as a principle, that the perfection of this kind consists in the close similitude of the work to that executed with the tool. But this absurd prepossession has been since worn out; and the method of working with aquafortis has been so far improved, that instead of being now deemed a spurious kind of engraving, it evidently appears, in many modem works, the* foundation of an excellence that could never have been produced without it; since, though the neatness and uniformity of the hatches which attend the use of the tool is more advantageous with respect to portraits, yet the liberty and facility of the other manner gives a much greater opportunity to exercise the force of genius and fancy in historical engraving, where the effect of die whole, and not the minute exactness in finishing all the parts, constitutes the principal value.

There are two methods practised of engraving in this way; the one with a hard varnish or ground, and the other with a soft. The former was at one time much used, being better accommodated to the intention of imitating the engraving with the tool; as the firmness of the body of the varnish gave more opportunity of retouching the lines, or enlarging them with the oval-pointed needles, called by the French échoppes, as was practised by Le Bosse and others for that purpose. The latter has now almost wholly superseded the use of the other, by the free manner of working it admits of; which affords a power of expression incompatible with the greater inflexibility of the hard varnish, that confines the lines and hatches to such a regularity and sameness, as give stiffness of manner and coldness of effect to the work.

The combination of the use of the tool and aquafortis, which are now both employed in many cases, has, however, given that perfection to engraving which it at present assesses. The truth and spirit of the outline which the method of working with aquafortis affords, and the variety bf shades which the different kinds of black produce in his way, as well as other means of expressing the peculiar appearance and character of particular subjects, furnish what was defective in the sole usc of the tool; whilst, in the other hand, the exactness and regularity of the lines, which are required for finishing many kinds of deigns, are supplied by the graver; and by a judicious application of both, that complete finishing is obtained which either of them alone must necessarily want.

The manner by which this is performed, is by covering he surface of the plate with a proper varnish, or ground, is it is called, which is capable of resisting aquafortis, and hen scoring or scratching away, by instruments resembling needles, the parts of this varnish or ground, in the places where the strokes or hatches of the engraving are intend’d to be; then, the plate being covered with aquafortis, the parts which are exposed by removing the ground or varnish are corroded or eaten away by it, whilst the rest, being secured and defended from the action of the acid, remain untouched.

There are two methods of etching, as has been already observed, the difference of which consists as well in the kind of the varnish or ground as in that of the aquafortis adapted to each kind; but the general methods of performing them are alike in both cases. These varnishes or grounds are distinguished by the names of hard or soft ; tor in their consistence, or the resistance which they give to the needles, lies their essential variation from each other. 1he hard varnish, it is with good reason conjectured, was not the first in use, but soon took the place of the other, and was for some time the most received in practice, on account of its admitting the work to be made more like that of the graver; the soft has since, however, in its turn prevailed, to the exclusion in some degree of the hard, except in the case of particular subjects, but not so entirely as to take away the expediency of showing how it is performed. The manner of etching with the soft varnish is now, however, one of the most important objects of the art of engraving; and it is at present in universal use, sometimes alone, but more frequently intermixed with the work of the tool, and in some eases with great advantage, even where the whole is intended to pass for being performed by the graver.

Preparation of the soft varnish, according to Mr Lawrence, am eminent English engraver at Paris. — "Take of virgin wax and asphaltum each two ounces, of black pitch and Burgundy pitch each half an ounce. Melt the wax and tiitch in a new earthenware glazed pot, and add to them, by degrees, the asphaltum, finely powdered. Let the whole boil till such time as that, taking a drop upon a plate, it will break when it is cold, on bending it double two or three times betwixt the fingers. The varnish, being then enough boiled, must be taken off the fire, and, letting it cool a little, must be poured into warm water, that it may work the more easily with the hands, so as to be formed into balls, which must be rolled up, and put into a piece of taffety for use.”

It must be observed, first, that the fire be not too violent, for fear of burning the ingredients, a slight simmering being sufficient; secondly, that whilst the asphaltum is putting in, and even after it is mixed with them, the ingredients should be stirred continually with the spatula; and, thirdly, that the water into which this composition is thrown should be nearly of the same degree of warmth with it, in order to prevent a kind of cracking that happens when the water is too cold.

The varnish ought always to be harder in summer than in winter; and it will become so if it be suffered to boil longer, or if a greater proportion of the asphaltum or brown resin be used. The experiment above mentioned, of the drop suffered to cool, will determine the degree of hardness or softness that may be suitable to the season when it is used.

Preparation of the hard varnish used by Callot, commonly called the Florence Varnish.—Take four ounces of fat oil, very clear, and made of good linseed oil, like that used by painters; heat it in a clean pot of glazed earthenware, and afterwards put to it four ounces of mastich well powdered, and stir the mixture briskly till the whole be well melted; then pass the whole mass through a piece of fine linen into a glass bottle with a long neck, that can be stopped very securely; and keep it for the use that will be below explained.

Method of applying the soft varnish to the plate, and of blackening it. — The plate being well polished and burnished, as also cleansed from all greasiness by chalk or Spanish white, fix a hand-vice on the edge of the plate where no work is intended to be, to serve as a handle for managing it when warm; then put it upon a chafing-dish, in which there is a moderate fire, and cover the whole plate equally with a thin coat of the varnish; and whilst the plate is warm, and the varnish upon it in a fluid state, beat every part of the varnish gently with a small ball or dauber made of cotton tied up in taffety; which operation smoothes and distributes the varnish equally over the plate.

When the plate is thus uniformly and thinly covered with the varnish, it must be blackened by a piece of flambeau, or of a large candle which affords a copious smoke; sometimes two or even four such candles are used together, for the sake of dispatch, that the varnish may not grow cold; which if it does during the operation, the plate must then be heated again, that it may be in a melted [7:9:374] state when that operation is performed; but great care must be taken not to burn it, which, when it happens, may be easily perceived by the varnish appearing burnt and losing its gloss. The following expedient is made use of for the more commodiously blackening the varnish, and is particularly necessary where the plates are large: Fix a strong hook in the roof of the room, through which pass four pieces of cord of equal length, at the end of which are fixed four iron rings of about four inches in diameter, for supporting the corners of the plate. The plate, being thus suspended in the air, with the varnished side downwards, may be blackened with great convenience; but this is not, however, absolutely requisite, excepting in the case of large plates, which could not, without difficulty, be suspended, unless this or some other such contrivance were made use of.

It is proper to be very cautious in keeping the flambeau or candle at a due distance from the plate, lest the wick should touch the varnish, which would both sully and mark it. If it appear that the smoke has not penetrated the varnish, the plate must again be placed for some little time over the chafing-dish; and it will be found that, in proportion as the plate grows hot, the varnish will melt and incorporate with the black which lay above it, in such a manner that the whole will be equally pervaded by it.

Above all things, in this operation, the greatest caution should be used to keep the fire all the time moderate; and to move frequently the plate, and change the place of all the parts of it, that the varnish maybe alike melted everywhere, and kept from burning. Care must also be taken, that during this time, and even till the varnish be entirely cold, no filth, sparks, or dust, fly on it; for they would then stick fast and spoil the work.

Method of applying the hard varnish. — This is precisely the same as that for the soft; it is spread equally over the warm plate with the taffety-ball, and smoked in the same manner; only, after it is smoked, it must be baked, or dried over a gentle fire of charcoal, till the smoke from the varnish begins to decrease; taking care not to overheat the plate, which would both soften it and burn the varnish.

The plate being thus prepared, and an exact drawing of the outlines of the design made upon thin paper, the other side of the paper must be well rubbed with chalk or Spanish whitening, or, which is better, with red chalk scraped to a powder: the loose chalk is then cleared off with a linen rag, and the stained side of the paper is laid upon the varnish, fixing the corners to the plate with wax or wafers, to prevent its shuffling; and with a blunted needle or pointer the drawing is slightly traced, and communicates to the varnish an exact outline of the design to be etched.

A variety of pointers is necessary for the work. Those used for the broad large strokes ought to be very blunt, exceedingly round, and well polished at the point; the sole of a shoe answers very well for polishing the points. The finest ought to be as sharp as a needle. If any scratches or false strokes happen in the working, they are to be stopped up with a hair pencil dipped in Venetian varnish mixed with lamp black, by which means these places will be defended from the action of .the aquafortis.

The next operation is that of eating or corroding the plate with aquafortis, in order to which a border of soft wax, being a composition of bees-wax melted and tempered with a little Venice turpentine and tallow, must be fastened round the plate about an inch high, in the form of a little wall or rampart, to contain the aquafortis. At one of the corners of this border a gutter is usually made, which serves for commodiously pouring the aquafortis off the plate. The plate being thus bordered, take a due quantity of the refiner’s aquafortis, mix it with half its quantity of com mon water, and pour it gently on, till it rise above a finger’s breadth above the surface of the plate; then, if a ]I things have been rightly conducted, it will soon be seen that the aquafortis exerts its action in the hatches which have been strongly touched; but those more weakly engraved will appear at first clear, and of the colour of the copper. The menstruum must therefore be suffered to continue on the plate till its effects become visible on the more tender parts; then the aquafortis should be poured off, the plate washed with clean water, and dried before the fire; after which take a small pencil dipped into the Venetian varnish, and cover with it the lighter parts of the plate. This being done, the aquafortis must again be poured on, and suffered to continue a longer or a shorter time, according to the strength of the menstruum or the nature of the engraving; after which it must be poured off as before, and the plate immediately washed with water.

It may not be improper to observe, that, when the aquafortis is on the plate, a feather should be used to cleanse away the foulness of the verdigris that gathers in the hatches when the aquafortis ∙operates on them, and to give it more room to exert its action; for by moving the aquafortis to and fro on the plate by the feather, and brushing away the black saline matter where it appears to be formed, the hatches will be cleansed, and the aquafortis exert its whole force equally on every part.

The plate being thus sufficiently corroded by the aquafortis, and well washed with water, it must be warmed at the fire, and the border of wax removed; after which it must be made hotter till the varnish melt; then it must be well wiped with a linen cloth, and afterwards rubbed well with oil of olives, when it will be ready to be retouched and finished by the graver.