CH. VII] PHOTOGRAPHS IN COLORS 245 



and any one familiar with the ordinary photographic processes can 

 succeed in color photography. It may be said in passing that the 

 pictures taken by this process are transparencies and must be looked 

 at as such to bring out the colors. Furthermore, as colors are truly 

 rendered only in daylight or by artificial daylight these transparencies 

 must be illuminated by natural or artificial daylight for a true render- 

 ing of the color. 



While these pictures cannot be used as negatives to give paper 

 prints in colors, they can be used as colored pictures to get the 

 proper negatives for printing by the three-color process, so that with 

 a good autochrome transparency, colored pictures for books and 

 magazines can be produced without any hand being taken in the 

 process by an artist; and for many things the transparency gives a 

 truth and delicacy in coloring not attainable by the artist's brush. 



COLLATERAL READING FOR CHAPTER VII 



Optic Projection, by S. H. & H. P. Gage. 



The Wratten Booklets on Photographic Plates and Color Filters. 

 The Photography of Colored Objects, by C. E. Kenneth Mees. 

 Photo-micrography. Published by the Eastman Kodak Co. 

 Seed Plates, formulae and directions. Eastman Kodak Co. 

 Furnished by the G. Cramer Dry Plate Company: 



Cramer's Manual on Negative Making and Formulas. 

 Isochromatic Landscape Photography. 

 The Photographing of Color Contrasts. 

 Dry Plates and Filters for Trichromatic Work, 

 Photo-micrographic and Spectrographic Color Filters. 



These brochures are naturally very recent and give the meat of the infor- 

 mation at present available on the kind of photographic plates available and 

 the proper color filters to use with them to produce the best effects with dif- 

 ferent colored objects in gross photography and in photo-micrography. 



For the sensitiveness of the human eye to the different parts of the spec- 

 trum see: Herbert E. Ives, Philosophical Magazine, Vol. XXIV, 6th ser. 

 Dec. 1912, pp. 853-863; P. G. Nutting, Transactions of the Illuminating 

 Engineering Society, 1914, pp. 633-642. 



