ANASTATIC PRINTING. Early in the month of November, 1841, the proprietors of the Atheneum received from a correspondent at Berlin, a reprint of four pages of the num ber of that journal which had been published in London only on September 25t1i. The copy was so perfect a facsimile, that had it not come to hand under peculiar circumstances, it would have been taken for two leaves out of a sheet actually printed in London ; the obser vable difference was, that the impression was somewhat lighter, and the body of ink less than usual. In reply to further inquiries, the correspondent at Berlin could only discover that the secret was said to be in the hands of a person at Erfurt. He had seen a facsimile of an Arabic MS. of the 13th century ; and another fac-simile of a leaf of a book printed in 1493—both such close copies as hardly to be detected from the originals, and both taken without injury to the originals. It was also stated that a prospectus was issued at Berlin, of a pirated edition of the Atheneum, to be produced in a similar way, and sold at a low price.
In January 1815, the Atheneum was enabled to announce that the inventor or discoverer of the method was a M. Boldermus, who had communicated the discovery to a person in London ; and to convince the proprietors of, that journal of the reality of the method, a page of L'Elusiration, French journal, was faithfully copied in a quarter of an hour. The method became known by the name of Anas tatie printing ; and many of the London jour nals directed attention to the subject. In the Art Union for February,1845, pages 40 and 41 of the number are printed from zinc plates ob tained by the Anastatic process. The compo sitors "set up" in the usual way, sufficient matter to fill up two quarto pages of the work, leaving spaces for three wood-cuts, three draw ings, and a few lines of writing in pen and ink, which were properly adjusted to the blanks left for them. All were alike copied or transferred to the zinc plates, and then printed from to the number of several thousands. The impres sions are fainter and less distinct than those from the original types, but they are unques tionably remarkable.
Professor Faraday explained the rationale of the Anastatic process in 1845, at the Royal Institution. The process depends on a few known properties of the articles employed. 1st. Water attracts water ; oil attracts oil ; but each mutually repels the other. 2nd. Metals are much more easily wetted with oil than with water; but they will readily be moistened by a weak solution of gum. Jai. The power of wetting metals with water is greatly inereasfid by the addition of phosphatic acid. 4th. A part of the ink of any newly printed book can be readily transferred by pressure to any smooth surface beneath ; if, for example, a Corner of a newspaper be fixed on a white sheet of paper; and then pressed or rubbed with a paper knife, the letters will be distinctly seen in reverse on the paper ; and indeed every one knows that if a book be bound too soon after the printing, the pages become disfigured by the setting or transfer of the ink upon the opposite pages. From these data the rules for the process are derived. The printed paper, whether letter-press or engraving, is first moistened with dilute acid, and then pressed with considerable force by a roller on a perfectly clean surface of zinc ; by which means every part of the sheet of paper is brought into contact with the plate of zinc. The acid, with which the unprinted part of the paper is saturated, etches the metal, while the printed portion sets off o n it, so that the zinc surface presents a reverse copy of the work. The zinc plate, thus prepared, is washed
with a weak solution of gum in weak phos phatic acid ; this liquid is attracted by the etched surface, which it freely wets, while it is repelled by the oil of the ink in which the writing or drawing on the plate is traced. A leathern roller, covered with ink, is then passed over the plate, when a converse effect ensues ; the repulsion between the oil, ink, and watery surface over which the roller passes, prevents any soiling of the unfigured parts of the zinc plate; while the attraction between oil and oil muses the ink to'be distributed over the printed portions. In this condition the anastatic plate is complete, and impressions are pulled from it by the common lithographic process. When it is required to apply the anastatic process to very old originals, which do not set off their ink on pressure, the page or print is first in a solution of potash, and then in a ;olution of tartaric acid: by which is produced s perfect diffusion of minute crystals of bi-tax-• trate of potash through the texture of the un printed part of the paper. As this salt resists oil, the ink roller may now be passed over the surface without transferring any of its contents, except to the printed parts. The tartrate is then washed out of the paper, and the opera tion is proceeded with as before, commencing with the moistening by nitric acid.
In No. 1135 of the Mechanic's Magazine, it is stated that Mr. Jobbins, the lithographic printer, took copies of printed pages by a pro cess analogous to that of anastatic printing, as far back as the year 1840 ; and in the same number Mr. Cocks of Falmouth states " In the year 1836 I introduced a process for the transferring of copper plate engravings (by the old masters), as well as letter-press printing, &c., to stone, zinc, tin, pewter, type-metal, fusible metal, lead, copper, glass, &c., and had impressions taken from each ; but the original subjects were destroyed by the chemical agents used. Since that time I have succeeded in transferring prints and letter press without even soiling the originals, fixing the same on metal, wood, or paper, and printing from the form any number of copies. The process is so faithful in its operation, that the finest line of the etching needle is preserved." It is evident, indeed, that anastatic printing is but an extension of processes known long before in England.
In 1818 Mr. Strickland and Mr. Delamotte instituted experiments with a view to ascertain how far the anastatic process would be avail able as a substitute for lithography. They succeeded in transferring or printing from drawings made on paper with lithographic chalk ; within an hour after the drawing was made, a perfect anastatic facsimile was pro duced, hardly to be distinguished from it. The chief difficulty here seems to be the pro duction of a kind of paper which shall possess a surface similar to lithographic stone. A mode has been devised of imparting to India paper a clear sharp granular surface, well fitted for the purpose as far as regards surface; but it is almost too tender in substance. Mr. Strickland found that metallic paper, used for metallic pencils, had the required surface. For fine subjects copied in this way, it is essential that the lithographic chalk be of a hard quality; and cut to a fine point.