Page:The American Cyclopædia (1879) Volume X.djvu/533

LITHOGRAPHY 527 pressure being applied, the ink adheres to the stone, for which it has a strong affinity. The back of the paper being moistened, the gum is loosened, when the sheet is readily removed, and the remaining gum is washed off with water. The stone is then treated precisely as though the drawing had been originally made upon it. The transfer process is also used to multiply copies for printing of the original drawing, and also to produce copies of engra- vings to be printed lithographically. For this purpose an impression from the original plate is taken upon transfer paper in transfer ink, which is composed mainly of the same ingre- dients as the chalk, only reduced to a semi- fluid state by oil or some other liquid. The number of copies which can be taken from a single lithographic drawing varies greatly. A fine crayon drawing will give from 500 to 3,000 good impressions ; an ink drawing about twice as many; while from drawings produced by the photolithographic process, described fur- ther on, as many as 30,000 have been obtained. It is customary to make one or more transfers, which can be substituted for the original draw- ing when worn out. Plates of metal, espe- cially of zinc, are sometimes used instead of stone, and in the same manner ; but stone is generally preferred. Stone is also frequently employed as a material upon which to engrave, in the same manner as upon a copper plate, only the lines are cut with a diamond point in- stead of a graver. For maps and plans this succeeds very well, the work being nearly as good, and the cost much less. Engraving upon stone, however, does not properly come under the head of lithography, the printing being per- formed as with copper plates, and not in the manner now to be described. Lithographic printing is a process partly chemical and partly mechanical. The ink used is the ordinary print- er's ink, composed essentially of linseed oil and lamp black, in a semi-fluid state, although other ingredients are usually added. (See INK.) The lithographic hand press consists of a roller revolving upon its pivots in an up- right frame, with a bed beneath it, moved back and forward by a winch. The stone is firmly secured upon the bed, and a moistened sponge is passed over it ; the water is repelled from the greasy lines of the drawing, but wets the uncovered parts of the stone. The ink is applied by means of the usual printer's roller ; it adheres to the greasy lines, and is repelled from the wet stone. The bed is then pulled under the roller, which is adjusted so as to give a heavy pressure. The ink is thus trans- ferred to the paper, which also absorbs the moisture of the stone. These successive ope- rations of wetting, inking, and pulling must be repeated for each impression. If the draw- ing is a large one, not more than V5 or 100 im- pressions a day can be taken upon the hand press; if the drawing is small, seven or eight times as many. Power presses have been con- structed within a few years capable of work- 501 VOL. x. 34 ing off 1,000 sheets an hour of any size. The principle, however, is the same as that of the hand press. The quality of the paper is a matter that requires attention. If it contain any gritty substances, it will soon act upon the stone ; plaster in its composition soon causes the lines to be clogged ; and alum attacks the gum and ruins the drawing. The printer should be able to appreciate the character of the work in hand, for upon his manner of ap- plying the ink the general tone of the impres- sions may in great part depend. Their per- fection is also in part due to the condition of the paper as to proper amount of moisture, and to the manner of regulating the press. Lith- ography was introduced into Vienna in 1802, into Rome and London in 1807, and into Paris in 1814. Everywhere it met with great favor, and especially in Paris. Artists of distinction practised and aided to perfect it ; and it was fashionable for the nobility to design on stone. Lemercier cultivated the art with the most dis- tinguished and long continued success. He invented the autolithographic or transfer pa- per ; and at the Paris exhibition of 1855 the medal of honor was awarded to Lemercier, who was then conducting a large establishment containing more than 100 presses and employing about 200 workmen. Count de Lasteyrie in- vented the method of facsimile printing, appli- cable to obtaining copies of characters that cannot easily be brought into ordinary typog- raphy, and also to maps in which all the details are lithographic, while the names of places are first produced upon the paper by ordinary print- ing. Engelmann by his knowledge of chemis- try was able to give a great impulse to the art of lithographic printing in colors, or chromo- lithography. Full treatises upon lithography were published in 1819 by Count Raucourt and Senefelder. In England its productions have been of a high order, especially in landscapes ; and the establishment of the Ackermanns in London was long famous for the fine speci- mens it furnished in this department, inclu- ding the productions of Hughe, Ward, Westall, Harding, Lane, and others. The art was intro- duced in America in 1821, and was practised by Messrs. Barnet and Doolittle in New York. There is a favorable notice of it, with some of the earliest specimens, in the "American Jour- nal of Science" for 1822. For many years, owing to the want of artists, it made little progress here, except for commercial purposes and the production of cheap prints ; but within the last few years many works of much merit, especially portraits, have been produced by Sarony and others. CHEOMO-LITHOGBAPHT is the art of producing by lithography works in which various colors are printed in a single picture. It is much used in various branches of ornamental work, and has been successfully employed in the production of pictures which are almost facsimiles of paintings and colored drawings. Each different color is printed sep- arately, from a stone which contains only the