PART II.-PRINTING PROCESSES. 



INTRODUCTORY. 



IT is hardly within our scope, and it is certainly not our in- 

 tention, to enter here at any great length into printing processes. 

 After a negative has been obtained the process of producing a 

 print or prints is purely photographic, and full instructions for 

 printing by the many processes available are to be found in 

 many purely photographic books ; for example, the reader 

 will find ample instruction on the subject in the book already 

 repeatedly alluded to : " The Processes of Pure Photography," 

 by Professor Burton and the present writer, forming one of 

 the series of publications of which the present book forms 

 another item. 



Still by attention to certain details in the ordinary photog- 

 raphic processes points preeminently important to the photo- 

 micrographer may be emphasized, and our present instructions 

 shall tend to work chiefly upon points affecting specially the 

 printing of a photo-micrographic negative. 



The processes we propose to treat thus briefly are : 



The albumen paper silver process 1 



The gelatine chloride emulsion process [ Paper prints by 



The gelatine bromide emulsion process j contact. 



The platinotype process j 



Enlarging on bromide paper. 



Lantern slides by contact and by reduction. 



