Stiping, or engraving in the dotted manner, was in a great measure intro duced by Bartolozzi, whose works in this way are astonishingly numerous, exclusive of those to which his name is affixed, and not the products of himself. Some pasto ral scenes, with figures, when printed in colours, have a pleasing effect ; and small portraits stipled will bear examination ; but historical subjects, which have great breadth of shade,. appear to no advantage engraved in this manner. Stipling is per formed by etching the plate with dots, and biting it, laying the shades with a tool for the purpose, using the graver and the dry point, and scraping off the rough ness thus occasioned.
Engraving in rIquatinta. The print from an aquatinted plate resembles a neatly finished drawing in Indian ink ; this effect is produced by corroding the plate between the particles of a material entirely different from the etching ground. The first step in this process is, to prepare a plate exactly in the way already de scribed, and etch the outlines of the sub ject to be aquatinted, which are to be slightly bitten, and the plate thoroughly cleansed. The substance used to form the grains of the subject (which may be common resin, burgundy-pitch, asphal tum, gum-mastich, or gum-copal, either separate or mixed) should be reduced to a fine powder and sifted, put into a piece of muslin, and holding it high above the plate, it must be struck against any sub stance held in the left band, till the show er of dust thus produced has covered the plate equally throughout ; preserving it carefully in this situation, the plate is to be heated sufficiently to melt the powder, which will make the grains as sume a circular form, and contract, leaving, when cold, a beautiful surface fit for the aqua fortis. Common resin is generally preferred for this part of the operation, but is less ble to be broken loose from the plat" during the process of biting.
The drawing to be copied must serve as the future basis of proceeding, is to be imitated in the following manner the perfectly white parts of the intended print are to be covered on the plate with the varnish mentioned in etching, by the use of a camel's-hair pencil , a border of wax must then be raised, and the aqua fortis, diluted, poured on ; the same me thod is afterwards practised in the stop ping out before recommended, except that the depth of the corroding cannot be so great as in the line manner.
In order to obviate any difficulties which occur in procuring sufficie nt depths of shade, a method has been invented, that enables the artist to produce an ef fect almost equal to the decisive touches of a brush filled with colour in drawing, which is the use of a liquid made with water, treacle, or sugar, and fine washed whiting, exactly of the consistence of In dian ink, and laid on the granulated sur face with a pencil, in the same free man ner adopted on paper ; after the above composition is thoroughly dry, the whole plate must be covered with a thin, weak, varnish of mastich, turpentine, or asphal tum, and, when dried a second time, the aqua fortis is to be applied, which imme diately breaking the varnish and whiting, will corrode the plate precisely in the marks of the pencil. The border of wax may be removed by heating the plate gently, and the ground varnish, &c. by oil of turpentine ; a little fine whiting and a clean rag will then render the plate fit for the printer.
As the manner of procuring the grain by heating the powdered substance scattered over the plate is liable to ob jections, on account of the difficulty of making the particles assume the desired coarseness, or the reverse, and the en graving so produced rapidly wearing out in the printing, another has been con trived, far more certain and satisfactory.
In this mode, common resin, mastich, or Burgundy pitch, is dissolved in highly rectified spirits of wine of the best quali •y, each of which produces different descriptions of grains ; but these sub stances may be mixed in such propor tions as the artist prefers, and he must re collect that the resin makes the coarsest ; to satisfy himself in this prrticular, the grain of every proportion should be tried on useless pieces of copper. Having a solution to his mind, it must remain un disturbed till every impure particle has subsided. The plate, polished and cleans ed with whiting, is then placed to re ceive the liquid, which being poured on it, is held slanting till the most fluid parts have run off; it is afterwards laid to dry, in the progress of which the resin gra nulates, and adheres firmly to the surface. The greatest precaution must be used in going through this process, as the in terposition of dust, grease, hairs, or fi bres of linen, will cause total derange ment; and even then it is subject to most vexatious uncertainty, often compelling the experienced artist to renew it to ob tain a good grain ; in short, the weather and untoward accidents frequently ruin his labours, though guarded against by every method his invention suggests. There is one advantage attending the pouring the liquid off, which is, that the heaviest particles of the resin will float to the lower side, and consequeutly leave a coarser grain there than above, much better suited to the deep shades of a landscape than if the granulations had been equally fine ; in large subjects the grain is sometimes laid coarse purposely in the parts requiring it.
Although a fine grain has a very pleas ing effect, and will bear close examina tion, it has several disadvantages; for this reason a medium description of gra nulation is preferable, which, admitting the aqua fortis freely to the copper, it bites deeper, and is less apt by acting la terally to force off the resin ; besides, the plate will of course afford a greater num ber of impressions.
Some hints have been given already for biting the plate ; but however useful those may be found in particular instan ces, there are others which can only be extracted from close application and ex periment, and those are often varied in their results: as an illustration, we may suppose an artist provided with several pieces of copper granulated, and trying each successively by his watch with spi rits of nitre diluted to the state of the air at the commencement of his operations, how many minutes are necessary to pro duce one tint, how many for a second, &c. granting him two hours for his ex periment ; during this interval a violent shower of rain may occur, which will Im mediately affect the acid, by weakening its properties in the same proportion as salt is observed to be dissolved by a hu mid atmosphere : thus it appears, a result obtained on a clear dry day will not suit a rainy one, and vice versa.
In opposition to this discouraging un certainty, and in opposition to the judg ment and preference of all true con noisseurs, aquatinted prints seem to in crease in value in the estimation of many persons; who forget that national taste should he improved by works of superi or execution, and not vitiated by being constantly familiarized to those produced by means which set genius at defiance.