Photogravure

lines which had been protected by the drawing were dissolved away. By treating the stone with an acid these lines were bitten or eroded, and could be printed from. Niepce afterward employed metal plates instead of the stone.Here we have the foundation for a number of printing processes of the present day, including photogravure.For many years, however, progress in processes for intaglio printing was very slow. In 1852 Talbot introduced a process termed photoglyphy, and in 1854 Paul PretschTable of Contents CONTENTS; PAGE; Introduction by the Editor-Early History of Photogravure-; Woodbury's Process-Other Methods, 5; Chapter I-The Negative-Quality best Suitable-Necessity forReversiug-Methods of Obtaining Reversals-TbePowder Process, ----,9; Chapter II-The Transparency-The Carbon Process-Cutting up the Tissue-Sensitizing-Drying-Exposing -Continuing Action of Light-Development-Carbutt's Transparency Plates, -------- 13; Chapter III-The Carbon Tissue-Sensitizing and Exposing-; The Actinometer, ------- 22; Chapter IV-Cleaning and Graining of the Copper Plate -; Grade of Copper Necessary-Where and How to Buy it, - 25; Chapter V-Development of Negative Resist on the Copper; Plate-Preparation for Biting with Acid through the Gelatine, 29; Chapter VI-The Acid Baths-How to Make Them and Method; of Biting through the Gelatine, - - - - - 32; Chapter VII,-Cleaning and Polishing the Plate, with Tools;