. The American annual of photography. , whichof necessity must be employed on account of the present daymethod of making negatives instantaneously. Perhaps evendirect colored positives could be obtained by a different silveremulsion and a different developer. Some of the developing agents presently known are of ananorganic nature, but most of them are organic. Of the or-ganic ones there are a large nurhber of hydrocarbons whichare mostly obtained from benzol and its derivates, from aniline the most beautiful colors are obtained bychemical process, could not perhaps the different co


. The American annual of photography. , whichof necessity must be employed on account of the present daymethod of making negatives instantaneously. Perhaps evendirect colored positives could be obtained by a different silveremulsion and a different developer. Some of the developing agents presently known are of ananorganic nature, but most of them are organic. Of the or-ganic ones there are a large nurhber of hydrocarbons whichare mostly obtained from benzol and its derivates, from aniline the most beautiful colors are obtained bychemical process, could not perhaps the different compositionsof the silversalts caused by the exposure to different degreesof light and colors decompose or form a chemical combinationwith aniline or a similar substance in such a way, so as tocause different colors to be created? Incidentally from thepoint of view of colorcreation, is it not peculiar that aniline,from which the most beautiful colors are produced, is ob-tained from coal tar which is a product of coal and that these 184. i I colors are created from a substance which in its original stateis black? And yet the physicists designate while namingwhite as the combination of all colors—black as the ab-sence of all colors. Now if instead of the direct way, the indirect way that ofusing color screens, should be employed, might not this methodbe changed from using color screens as made at present fromartificial color material, to more natural color screens producedfrom the salts of silver? It is peculiar that the color screens,as at present employed,*consisting of an aggregation of minuteparticles dyed in colors to represent the primary colors whichare either irregularly constituted when incorporated directlyin the photographic plate or in regular forms in the separatescreen method, have very often the chocolate or other similarcolorations, resembling the colors of silver salts after exposureto light, for instance like Cary Leas photosalts which he em-ployed in his days,


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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyorktennantandw