PHOTOGRAPHY, SCIENTIFIC ASPECTS - 



chromes, although the colors differ appreciably, "the 

 green tending more toward yellow and the blue being 

 less violet." 



The great drawback to the autochrome plate is the 

 loss of light. This defect is necessarily present wher- 

 ever a color screen of any description is used, but the 

 sensitiveness of the autochrome plate is comparatively 

 small owing to the imperfectly transparent nature of 

 the starch grains as well as the black filling-in material 

 of the unavoidable interstices. Therefore, the physi- 

 cist is still laboring to obtain increased brilliancy and 

 brightness in the picture. 



With this end in view Mr. Jan Szczepanik, by taking 

 advantage of the property possessed by certain sub- 

 stances of absorbing coloring matter from others, has 

 recently produced a plate that possibly may show the 

 way to a considerable advance in indirect color pho- 

 tography. 



"Szczepanik prepares three solutions of gelatine 

 or gum-arabic. Each solution is colored with a suitable 

 dye, and is then evaporated to dryness. The particu- 

 lar dyes used must, of course, have a preference for 

 collodion. The solid masses of gelatine or gum- 

 arabic obtained by evaporating the solutions are finely 

 powdered, and the three powders of different colors 

 are carefully mixed. The mixture of these colored 

 powders is then sifted over a slightly moist collodion 

 plate by means of a special apparatus. The coloring 

 matters migrate from the gelatine powder into the 

 collodion film, producing a mosaic of small colored 

 patches similar to the starch granules of the autochrome 



[245] 



