THE PHOTOGRAPHY OF COLORS. 539 



THE PHOTOGRAPHY OF COLORS. 



By M. LAZAEE WEILLEE. 



IT is difficult to give a simple explanation of color. Physicists 

 declare that it is the result of a vibratory movement; and 

 metaphysicians who listen to them pretend to comprehend this. 

 Although it is not clear, this definition is nevertheless the only 

 one it is possible to give. There exists a vibratory movement 

 which is translated into heat, light, and electricity. There are 

 possibly also movements that determine the various psychological 

 23henomena other vibrations no less confused, no less vague, no 

 less mysterious to our minds than the physical vibrations. 



Many persons will be surprised when they are told that M. Lipp- 

 mann, the discoverer of photography in colors, was never engaged 

 in photography. He discovered in the play of luminous vibra- 

 tions what he was trying to define in the theory of sonorous vibra- 

 tions. Being charged with the exposition in his lectures at the 

 Sorbonne of the principles of acoustic phenomena, he sought espe- 

 cially to demonstrate to his students that the pitch of the sound 

 given out by an organ pipe depended on its length and not upon 

 the particular metal of which it was constructed. He was at once 

 struck with the results that might be drawn from this phenome- 

 non ; he asked if it would not be possible to transport into the 

 domain of light the curious property that seemed to be involved 

 in that of sonorous vibrations. This conception, in its elegant 

 simplicity, might be said to be a conception of genius. There was 

 nothing in it like the attempts that were made earlier in the cen- 

 tury to fix colors photographically. The first experiment in this 

 direction was made in 1810 by Prof. Seebeck, at Jena. He tried 

 to impress the colors of the solar spectrum on a paper covered 

 with a film of chloride of silver. His experiments, though not 

 successful, were much talked about. They were taken up again 

 in earnest in 1841 by Sir John Herschel. Failing with chloride- 

 of-silver paper, he tried bromide and iodide of silver, and natural 

 products, such as guaiacum root. He succeeded by some of these 

 processes in temporarily fixing a few colors on sensitive papers. 

 Such results were encouraging. We were then at the beginning 

 of photography. But these successes were soon surpassed by the 

 experiments of Edmond Becquerel, who succeeded, in 1848, in ob- 

 taining upon a silver plate covered with a film of violet subchlo- 

 ride of silver the impression of all the colors of the solar spectrum. 

 Unfortunately, the colors stored up in this manner vanished as 

 soon as the plate was exposed to the light. All attempts to pre- 

 serve them by means of a fixing bath failed. At every effort the 

 color disappeared. The impression of the spectrum colors by the 



