8 Thorp, Grathig Films arid Colour Photography. 



made into which the three gelatine pictures can be 

 impressed. Reproductions might then be made in trans- 

 parent celluloid after the manner of the grating films, and 

 mounted, when the effect produced would be precisely- 

 similar to that by the original superposed pictures. 



Even if this is not found practicable, reproductions of 

 the pictures in celluloid can be made, thus obviating the 

 necessity of using films, printing, and washing. 



In case it is found practicable to take the three 

 pictures on one film, then by silvering the film, mounting it 

 on a concave surface, and viewing by reflected light, the 

 spectrum-forming lens at least can be dispensed with, as 

 well as the viewing lenses, unless stereoscopic effects are 

 desired. 



The same effect would be produced from a flat surface 

 if the rulings were circular and variably spaced, and in 

 such a case our best ornithological, botanical, zoological, 

 &c., books, at least, might be illustrated in a manner, 

 failing some simpler new method, which would yield 

 pictures more nearly corresponding to those of the objects 

 themselves than is possible to obtain by any printing 

 process. 



In the case of designs no printing at all is actually 

 necessary. All that is required is to obliterate the parts 

 of an ordinary celluloid film which are not required to be 

 coloured, by some transparent medium, and surperpose in 

 the ordinary way. This will probably be found the method 

 most applicable to new designs, but where an existing 

 design is required to be reproduced, photography and 

 printing as described would be necessary. 



