Autography is not confined to the transferring of writings or drawings done with autographic ink ; by its means a transfer may be obtained from a sheet of ordinary printed paper, and with such exactness, that it would be impossible, excepting to well-practised eyes, to perceive the least difference between that printed in the usual way, and that which was the result of the autographic process. This mode is very useful when it is desired to unite oriental cha racters, which might not be possessed with words, or lines composed in ordinary typography. In this way have been executed, in the office of the Count M. C. de Lasteyrie, at Paris, (from whose papers on this subject, contained in the Journal des Connaissancez Usuelles, and translated by the learned editor of the Prank& Journal, our account of this art ia largely indebted,) many pieces, in which the French or the Latin language was intermixed with words or phrases in Chinese or Arabic. In the same way have also been executed typographic maps, in which all the details were lithographic, while the names of places were at first produced by typography, and afterwards by autography. This operation is begun by composing and arranging, in a typographic form, the words, the phrases, or the lines, as they ought to stand. The autographic paper is printed on by this form, and the words in the oriental languages are afterwards written in the spaces which had been left for them ; the whole is transferred to a stone, which is prepared for the purpose, and from which the impression is taken in the usual manner. The same mode is pursued in making geographical maps. After having printed the names on autographic paper, the other parts of the map, but without the names, are drawn immediately on the stone; and after having printed the names on white paper, the map drawn upon the stone, is printed on this same paper.
Maps, or line engravings on copper, where the work is not very close, may be multiplied in a similar way. For this purpose the plate of copper is covered over with the autographic ink, diluted to a convenient consistence. Instead of the autographic ink, a composition is sometimes used, made of one ounce of wax, one ounce of suet, and three ounces of the ink with which the ordinary impressions in lithography are taken. The whole is warmed and mixed well together, and there is a little olive oil added to the composition, if it is not liquid enough to spread itself over the plate ; the plate ought to be warmed as usual. After having taken the impression in the rolling press on a sheet of autographic paper, the transfer may be immediately made on the stone, after having rubbed it with a sponge, dipped in turpentine. It is necessary to give three, four, or even more strokes of the press, increasing the pressure at every successive stroke ; the other processes, which we have already described, are likewise to be followed. It is well to wait twenty-four hours before preparinp the stone, in order that it may be better penetrated by the transferring ink ; it is then gummed and washed, and is ready for use. This process, which has not yet come much into use amongst lithographers, ments the attention of artists; for it affords the means of re-producing and multiplying geographical charts, and some kinds of engravings indefinitely, so that they might be furnished at a quarter of their present actual value • in fact, all those which are done in lines, or those in which the shadows are boldly executed, are capable of re-producing good impressions by means of autography. The operation
becomes extremely difficult when it is necessary to transfer fine line engrav ings; the lines of these are so delicate, and so near to each other, that they either do not take well on the stone, or are apt to be crushed and confounded together by the effect of the pressure. Much practice and address are neces sary to obtain tolerable impressions ; and this part of the art requires improve ment. In the office of M. de Lasteyrie, they had succeeded in transferring to stone a small highly-finished engraving, which had been printed on common half-sized paper. After having dry-polished a stone very perfectly, it was warmed, rubbed with spirits of turpentine, and then the engraving was applied to it. This had, however, been previously dipped into water, then covered on the reverse side with turpentine, passed again through the water, so as to • remove the superfluous turpentine, and then wiped with unsized paper. In this state the engraving, still damp with the turpentine, was applied to the stone and sub mitted to pressure, when it afforded very good impressions; the preparation not being applied until it had remained on the stone for twenty-four hours. The difficulties increase, of course, in proportion to the size of the engravings which it is desired to transfer to the stone. Attempts have been made to transfer old engravings ; they have, however, succeeded but imperfectly. It would be rendering an essential service to the art to discover a mode of re-pro ducing old engravings by means of autography ; the undertaking presents difficulties, but from the attempts made, success does not seem improbable.
Printing from two or more Stones with different Coloured Inks.—This is managed by preparing a composition of two parts of wax, one of soap, and a little vermilion. Melt them in a saucepan, and cast them into sticks • this must be rubbed up with a little water to the thickness of cream, and applied to the surface of a polished atone. An impression is taken in the common way from a drawing, and applied to • stone prepared in this manner, and passed through the press, taking care to mark, by means of this impression, two points in the margin corresponding on each of the stones. The artist, having thus on the second stone an impression from the first drawing to guide him, scrapes away the parts which he wishes to remain white on the finished impression. The stone must now be etched with acid stronger than the common etching water, having one part of acid and twenty of water; the whole is then washed off with turpen tine : this plan is generally used in printing a middle tint from the second stone ; the black impression being given from the first stone, a fiat transparent brownish tint is given from the second, and the white lights are where the paper is left untouched. The dots are necessary to regulate the placing of the paper on the corresponding parts of the two stones.