[Illustration] COLLOTYPE AND PHOTO-LITHOGRAPHY PRACTICALLY ELABORATED BY DR. JULIUS SCHNAUSS, Member of the Imperial German Academy of Naturalists, &c. TRANSLATED, WITH THE AUTHOR’S SANCTION AND ASSISTANCE, BY EDWIN C. MIDDLETON. TOGETHER WITH AN APPENDIX ON STEAM PRESSES, BY THE TRANSLATOR. LONDON: ILIFFE AND SON, 3, ST. BRIDE STREET, LUDGATE CIRCUS, 1889. PRINTED BY ILIFFE AND SON, 3, ST. BRIDE STREET, LUDGATE CIRCUS, LONDON, E.C. WORKS: COVENTRY. CONTENTS. CHAPTER. PAGE. I. Introductory 9 II. Bichromates in Conjunction with Organic Substances 12 III. Summary of the more important Printing Processes with Chromated Gelatine 18 IV. Collotype Apparatus 25 V. Chemicals and Materials for Collotype 46 VI. Preparation of the Collotype Plate 59 VII. Negatives suitable for Collotype 72 VIII. Printing in the Press 88 IX. Finishing and Varnishing Collotype Prints 96 X. Other Collotype Processes 102 XI. Failures in Collotype: In the Preparation of the Plates 107 XII. Investigations on Collotype 114 XIII. Collotype in Natural Colours 119 XIV. Magic Prints 122 XV. Photo “Glass” Printing 124 XVI. Allgeyer’s Collotype Process 127 XVII. Practice of Photo-Lithography 130 XVIII. Autography 135 XIX. Negatives for Photo-Lithography 149 XX. Application of the Carbon Process to Photo-Lithography 155 APPENDIX. Steam Presses 162 TRANSLATOR’S PREFACE. The impossibility of obtaining any work in the English language on the subject of Collotype first led to my translation of the German work of Dr. Schnauss, and the fact that no work has hitherto appeared fully dealing with the matter is the excuse I offer for the present publication. The translation is necessarily one of considerable freedom, but it is offered as containing all the information to be found in the original, and in addition, considerable extensions, made with the author’s consent. The omission of the chapter dealing at length with the steam machine was necessitated by the fact that the rotary machine there described is no longer manufactured.