ON WOOD.

As we have shown in our article on Printing, Wood-engraving was in fashion prior to the invention of printing. We are informed by Albert Durer that Engraving on Wood was invented about the year 1520; he may be a good authority in some matters, but in this he has committed a mistake of nearly one hundred years; seeing that there is at least an impression of one engraving on wood, the representation of the Creation, which was in existence prior to 1430. It was undoubtedly a piece of rough workmanship; but what could be expected at that early period of the art? It has been, however, gradually improving ever since, and it has now attained a point of excellence equal to any of the fine arts, and calls forth the admiration of every lover of the beautiful. It would be invidious to select any of the numerous artists now flourishing—perhaps it would be difficult to make a selection where so many are upon an equality; and we are of opinion they themselves are more willing to accept the public approbation as their reward, than any praise our pen could bestow. All we can do is to recommend our readers to examine for themselves; they have abundant opportunities in the numerous illustrated publications that are daily issued from the press, and bestow that meed of praise upon the respective artists they may deem proper.

The process of engraving on wood is diametrically distinct and opposite to that of engraving on copper or steel; as in the former, the shades are produced by the parts of the work which are made most prominent, and obtrude upon the surface of the substance; whence its chief merit has been regarded in leaving broad and well-proportioned lights. The parts to produce this effect being of necessity excavated, great art and a masterly judgment are necessary to effect this, and at the same time not to weaken the substance, lest it should be injured in the pressure necessary to produce an impression.

The substance usually employed for these engravings is wood of a close grain; on this account box-wood is generally selected. The impressions are obtained from wood-engravings upon exactly the same principle as are the impressions from typography; and they can also be worked off at the same time with the descriptive text. This is a superiority which wood possesses over other engravings, and recommends itself to publishers on account of the immense saving in the expense of a double process in procuring copper-plate illustrations for typographical works, and enables them to keep pace with the ruling passion of this literary era—cheap publications.

ON COPPER.

The art of engraving on copper plates, for impressions, is alleged to have been invented by Peter Schoeffer, one of the early printers, and son in-law of John Faust, about the year 1450. The honour of this invention is also claimed by a Florentine goldsmith of the name of Finguires, who dates his invention in 1540. This artist having used liquid sulphur to take an impression of some chasing and engraving he had made, observed a blackness produced by the sulphur left in the deepest parts of his work, whence he obtained an impression on paper.

But we have no hesitation in giving the preference to Schoeffer, who, we have previously remarked, was of an ingenious turn, and assisted Guttenburg in producing moulds for casting his types; in addition to which, some of the books printed by him are ornamented with head and tail-pieces, with other rude attempts at engraving; and likewise because Schoeffer’s claim to the honour was acknowledged before Finguires was born.

Of engraving there are various kinds; that called by connoisseurs, the legitimate mode of engraving, is what is termed the line or stroke mode. Numerous have been the British artists who have excelled in this style, in affording the means of multiplying our graphical productions.

The next species of engraving we will notice is called the stipple, or chalk style,—imitations of chalk drawings. Portraits and historical pieces are executed in this style, which the celebrated Bartolozzi brought to perfection.

The third species we will mention, cannot properly be called engraving; the effect is produced by scraping and rubbing; this kind is called chiaro obscuro, or mezzotinto; producing prints which have the effect of Indian ink drawings.

A fourth species of engraving is what is commonly used for landscapes, which produces an effect like a pencil water-colour drawing; which is called aquatinta.

In all of these kinds of engravings upon copper the artists find the sulphuric acid, or aquafortis, a most powerful agent. Sometimes, indeed, it is suffered to execute the whole of the process of the graver, especially when it is called an etching.

For the same reasons as those mentioned with regard to wood engravers, we shall abstain from naming any of the very eminent artists now living.

We have already observed the mode of obtaining similar effects from wood and copper, are opposite to each other. The manner in which impressions from wood engravings are obtained, has likewise been noticed; and it remains that we observe the mode by which impressions are obtained from copper-plates. The plate is covered with appropriate ink; the surface is then carefully cleansed, leaving ink only in the excavations or lines in the copper. The plate and paper are passed through a roller press of great power, the roller being covered with a blanket, which presses the paper into all the crevices of the plate, and brings away the ink there deposited.

ON STEEL.

For several years steel has been used in great quantities, instead of copper-plates, by engravers. By this fortunate application of so durable, and it may be added, so economical a material, not only has a new field been discovered admirably suited to yield in perfection the richest and finest graphic productions, which the ingenuity of modern art can accomplish, but to do so through an amazingly numerous series of impressions without perceptible deterioration. The art of engraving on iron or steel for purposes of ornament, and even for printing, in certain cases, is by no means a discovery of modern times; but the substitution of the latter for copper, which has invited the superiority of the British burin to achievements hitherto unattempted by our artists, is entirely a modern practice.

In the year 1810, Mr. Dyer, an American merchant, residing in London, obtained a patent for certain improvements in the construction and method of using plates and presses, &c., the principles of which were communicated to him by a foreigner residing abroad. This foreigner was Mr. Jacob Perkin, an ingenious artist of New England, and whose name has become subsequently so extensively known in this country, in connection with roller-press printing from hardened steel plates. The plates used by Mr. Perkins were, on the average, about five-eights of an inch thick; they were either of steel so tempered as to admit of the operation of the engraver, or, as was more generally the case, of steel decarbonated so as to become very pure soft iron, in which case, after they had received the work on the surface, they were case hardened by cementation.

The decarbonating process was performed by enclosing the plate of cast steel properly shaped, in a cast iron box, or case, filled about the plate to the thickness of about an inch with oxide of iron or rusty iron filings; in this state the box is luted close, and placed on a regular fire, where it is kept at a red heat during from three to twelve days. Generally about nine days is sufficient to decarbonize a plate five-eighths of an inch in thickness; when the engraving or etching has been executed, the plate is superficially converted into steel, by placing it in a box as before, and surrounding it on all sides by a powder made of equal parts of burned bones, and the cinders of burned animal matter, such as old shoes or leather. In this state the box, with its contents, closely luted, must be exposed to a blood-red heat for three hours; after which, it is taken out of the fire, and plunged perpendicularly edgeways into cold water, (which has been previously boiled) to throw off the air. By this means the plate becomes hardened without the danger of warping or cracking. It is then tempered or let down by brightening the under surface of the plate with a bit of stone; after which it is heated by being placed upon a piece of hot iron, or melted lead, until the rubbed portion acquire a pale straw-colour. For this purpose, however, the patentee expressed himself in favour of a bath of oil heated to the temperature of 460 degrees, or thereabouts of Fahrenheit’s scale. The plate being cooled in water, and polished on the surface, was ready for use.

A more material peculiarity in Mr. Perkins’ invention, and one which does not seem to have been approached by any preceding artist, was the contrivance of what are called indenting cylinders. These are rollers of two or three inches in diameter, and made of steel, decarbonized by the process above described, so as to be very soft. In this state they are made to roll backward and forward under a powerful pressure, over the surface of one of the hardened plates, until all the figures, letters, or indentations are communicated, with exquisite precision, in sharp relief upon the cylinder; which, being carefully hardened and tempered, becomes, by this means, fitted to communicate an impression to other plates, by an operation similar to that by which it was originally figured. It will be obvious that one advantage gained by this method must be the entire saving of the labour and expense of re-cutting in every case, on different plates, ornaments, borders, emblematical designs, &c., as these can now be impressed with little trouble on any number of plates, or in any part thereof, by the application of the cylinder. At first sight, the performance of such an operation as the one now alluded to may appear difficult, if not impracticable; and, indeed, many persons on its first announcement were disposed to doubt or deny its possibility altogether. With a proper and powerful apparatus, however, this method of transferring engravings from plates to cylinders, and vice versa, is every day performed with facility and success, not only in the production of bank notes, labels, &c., but in works exhibiting very elaborate engravings.