CHAPTER IX. 



LANTERN SLIDES ON DRY PLATES. 



HERE are many dry collodion methods which, 

 were originally designed for ordinary nega- 

 tive work in the camera, but which have 

 long ago been superseded by the far quicker and 

 more certain gelatine process. Some of these plates, 

 however, although they have been discarded for the 

 main purpose of photography, are still used by many 

 workers for the manufacture of lantern-plates where great 

 speed is a matter of secondary importance. 



For many of these processes the silver bath is still 

 required, the plate after being sensitised therein, being 

 flowed over with some preservative solution, the function 

 of which is to keep the pores of the collodion film in such 

 a condition that it will not dry into a horny state, im- 

 permeable to any developer which may later on be 

 applied to it. As full particulars of these processes can 

 be found in most photographic text-books, I shall content 

 myself with giving here only a brief survey of them, 

 reserving details of working for the more modern methods 

 of producing lantern-slides on gelatine plates. 



