Lithography.

Manufacturer and Builder ?, 1890

The art of printing from stone dates from the year 1800, and its invention is due to the ingenuity of Aloysius Senefelder, a musician of Munich. It is a bit of popular history — which may or may not be true — that it was his custom to arrange his musical compositions upon slabs of a slaty or lammelar limestone found in the neighborhood, and that a memorandum of this kind having one day fallen accidentally into a vessel containing greasy water, he noticed with surprise, on withdrawing the stone, that the grease had attached itself only to the characters he had written thereon, while the rest of its surface remained quite clean. Such a circumstance might have escaped the notice of a less observant man, or, if noticed, might have had no significance; but to him it suggested possibilities of practical utility, which in the course of a few years developed in the invention of the now widelypracticed art of lithography.

The development of his invention required extended experimentation, involving the selection of suitable crayons with which to draw upon the stone, and of appropriate agents to act upon it, and the contriving of a suitable press in which to make the impressions; and these details, to one who had neither the advantage of chemical knowledge nor the training of a mechanic, were problems of much difficulty. They were, however, successfully solved.

It is said, also, that he endeavored at first to keep the method a secret; but the curiosity aroused by the beauty of the work he produced, was so great, that, little by little, the nature of his operations became known, and in France and elsewhere ingenious artizans succeeded in time in working out the details for themselves, and the inventor did not reap the benefits from his process to which he was justly entitled.

It was not long before the great value of the new mode of printing came to be appreciated, and the art itself became fully established as greatly superior, in convenience and economy, to all other processes as a means of producing illustrations, especially of works of art, of architecture, and the like, and it gave a powerful stimulus to the publication of illustrated books, as it gave the artist a scope for the exercise of his skill which hitherto had been denied him. Thus the art immediately took the foremost rank in the field of the graphic arts, and this rank it retained unchallenged down to the period when the invention of photography called into life a powerful rival. But this rivalry, curiously enough, was destined to be changed to a friendly union by the application of what has since come to be known as photolithography, in which the two processes of photography and lithography are ingeniously combined. But of this we shall come to speak later.

The description of the art of lithography properly begins with the stone, which forms the printing surface. For this purpose, an exceedingly dense, but absorptive, limestone is found to be best adapted, and that which is found in the neighborhood of Ellin and Solenhofen, in Germany, has always maintained its superiority. Similar stones have been found in France, England, and elsewhere in Europe, and in Kentucky in this country, but they are said to be inferior to those above named. The lithographic stone is prepared for use by polishing their surfaces by friction against one another, with a suitable abrading material. When they have been brought to a true surface, they are finished by different processes, according to the uses for which they are intended, as, for example, whether they are to be used for receiving written characters or drawings, etc., the finish of the surface being accordingly either very smooth, or given what is technically called a "grain." When finished, ready for use, the stones are carefully protected on their prepared surfaces by a covering of paper, and in this condi! Lion are sent out for use.

The course of the operations of lithography are, briefly, as follows: We will take the most common case of written characters or a line drawing, which is to be reproduced. For this purpose, the draughtsman uses either a ruling pen, or one made of thin metal strips, or a fine brush, using as a vehicle an ink of peculiar composition, known as "lithographic" ink. The composition of this ink varies considerably. Ordinarily it contains wax, guns mastic, guns lac, soap and lampblack. It forms a solid substance, which, as required for use, is rub bed down with water to a liquid of the proper consistency to flow properly from pen or brush. The characters or lines of the drawing must, of course, be drawn on the stone in the reverse order, so that when printed they will appear in the right position; and the artist must acquire proficiency in this mode of delineation. As an aid to enable him to inspect the appearance of his sketch from time to time, a lookingglass is used, in which he can view the reflected image of his work, which gives it in its correct position.

Where the effect of shading is required, the artist uses a lithographic crayon, the constituents of which are wax, soap, grease and lampblack, with the aid of which the required drawing is made in reverse position on the stone, in the same manner.

When the sketch is finished, the next operation consists in pouring over the stone a liquid containing nitric acid and gum. This liquid acts on all portions of the stone that are not protected by the ink or crayon; they are thus rendered incapable of receiving printing ink, while the protected parts have the impression more strongly fixed, for when the stone has been well washed with water, and turpentine is afterwards applied — by which all the material used in marking the design on the stone is dissolved — the apparently obliterated characters of the sketch reappear, when, after the stone has been lightly wiped with a sponge moistened with water, a roller, charged with printer's ink, is passed over the stone. The ink is taken up by the stone only at those places which have not been acted upon by the acid. The impression is then made by laying a sheet of moistened paper on the damp stone and applying pressure, by means of a roller, under which the stone is passed. After each impression, the stone is again moistened, and the inking is repeated.