2539152The New Student's Reference Work — Lithography

Lithog′raphy, the art of printing from stone. Chalky stones, as limestone, absorb grease and water readily. If a greasy line is drawn on a prepared stone, this line can be removed only by taking away the surface so far as the grease has penetrated. If water is put on this prepared stone after the greased line has been drawn, the water remains on those parts not covered with the grease. If a roller covered with greasy ink is passed over the stone, the ink will cover the greased portions, and the parts wet with water will repel the ink and remain clean. If a piece of paper is now put on the stone, it will receive an impression in ink of the greasy line. These are the elements of lithographic printing.

The art was invented by Senefelder in 1796. In 1800 he patented his invention in Bavaria, most of the German states and Austria. His establishments in London and Paris did not do well for the new art was guarded with such secrecy and jealousy as to retard progress, and many years passed before it was brought to perfection. Various methods are used, as drawing on stone with pen or brush, using liquid ink; drawing on paper and transferring to stone; engraving on stone; drawing on stones with crayon or solid ink and transferring from engraved plates or woodcuts.  The printing from all is nearly the same.  The stones are composed of lime, clay and silicon earth, and vary in color.

Zincography, the invention of Eberhard of Bavaria, is an application of this art to zinc instead of stone.  Its only advantage is in connection with large subjects, the zinc being more portable and less liable to break than stone.  In chromo-lithography, by which colored pictures are produced, a large number of stones are used, one for each separate tint, sometimes as many as 20 or 30 colors being printed.  Photo-lithography is used in printing plans, maps etc., which are copied from a photographic negative and then transferred to the stone.