Original Plate

"The frontispiece consists of two copper-plate engravings, one printed from an engraved plate, and the other from an electrotype copy taken from it in the mode described on page 51. The engravings are introduced for the purpose of showing the accuracy of the copies obtained by this process."

This book contains a full description of the electrotype process, critical to many subsequent photomechanical patents and methods. The catalogue contains optical materials such as magic lanterns, slides, and lists of camera obscura, and is typical of the offerings of philosophical instrument dealers at this time, who were the main suppliers to photographers. The electrotype process was important in photomechanical printing in that it was first used to copy daguerreotypes and was also used in experiments as a printing surface. Eventually Paul Pretsch used it with his photo-galvano-graphic process, and it was used continuously thereafter as a device to duplicate surfaces for printing in practically all the relief processes and some intaglio.