ZINCOGRAPHY is essentially the same art as lithography (q.v.), zinc-plates being stituted for those of stone. One form of the art is described under the name of Antista tic printing (see PRINTING). A style of it, called paneiconograpby, brought forward by Gillot of Paris, for the purpose of reproducing, by lithographic. autographic, or typographic proof, any crayon or stump, or any engraving from wood or copper, is thus described: A plate of zinc finely polished is prepared, and if an original drawing is to he copied, it is done by the artist in lithographic crayon on this plate; autographic writing done with the crayon, lithographs, and fresh proofs of wood or copper-plate engravings, must be transferred in the usual way to the surface of the plate; and while -still wet. an ink-roller is passed over, so as to give a deeper impression. Eosin very finely powdered is then sifted over, which adheres to the wet ink, and be comes consolidated, so that the superfluous powder is easily brushed off from the parts not covered with ink. The plate is next placed with its face upward in a shallow trough containing dilute sulphuric or hydrochloric acid saflicient to slightly cover it; the trough is then gently rocked, so as to make the acid flow backward and forward over the plate, and if this be continued for some time—an hour or upward—all the parts of the plate not covered with the ink and rosin are etched deep enough to be used as a relief-plate for printing from. In impressions where there are large interspaces, it is
usual to saw them out; and in some cases, where it is found that the relief is not suffi ciently high, the raised parts are re-inked, and again covered with the rbsiu, and sub mitted a second time to the action of the acid. Old engravings may be transferred by laying them to become damp on a board wetted with acidulated water, and then applying the ink-roller to the face of the engraving: the ink only acts upon the ink lines of the engraving, and is repelled by the acid moisture which has been imbibed by the uncovered white spaces. A slight pressurewill then easily produce a copy on the polished zinc-plate, which is perfected by the subsequent operations.