172 COLOR PHOTOGRAPHY. 



Again the color of no natural object is ever pure. 

 Analyzed, some rays of the spectrum are absorbed, some 

 reflected ; besides a certain amount of white light is re- 

 flected from all surfaces except dead black. Were it 

 not for this, all ordinary photographs would present 

 more striking contrasts than now. 



i^ow in exposing a sensitizing plate, we have all parts 

 acted upon by the white light according to length of ex- 

 posure : certain molecules specifically decomposed ac- 

 cording to the colors of the object focused upon the 

 plate. 



As it is a property of the silver salt under these con- 

 ditions to darken, the molecular changes affected corres- 

 pond to the impact or impression of the light waves 

 striking it, we have as a result of ''development," which 

 is a dissolution of the silver salt which has not been act- 

 ed upon by the light, and the subsequent fixation or 

 rendering permanent by the application of certain 

 chemicals to the plate, a picture presenting simply con- 

 trasts. 



Every one who has looked upon the reflection of a 

 landscape in a Claude Lorraine mirror, or who has mere- 

 ly focussed an ordinary landscape upon a camera ground 

 glass, must have given expression to a longing that some 

 process would be discovered whereby the beautiful re- 

 flected picture could be reproduced in the finished 

 photograph. 



The distortions of optics and the unvarying laws of 

 chemical action have discouraged the efforts of many a 

 would-be photographic artist. 



From the very earliest date of photographic printing, 

 long before the discovery and perfection of the present 

 methods of photography, long before Daguerre's great 

 discovery, efforts were made by distinguished scientists 

 to reproduce the colors of the spectrum in a photo- 

 graphic picture. Seebeck, of Jena, in 1810 discovered 



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