Tables 374-376 



TABLE 374. — Variation of Resolving Power with Plate and Developer 



345 



The resolving power is expressed as the number of lines per millimeter which is just resolvable, the 

 lines being opaque and separated by spaces of the same width. The developer used for the comparison 

 of plates was Pyro-soda; the plate for the comparison of developers, Seed Lantern. The numbers are 

 all in the same units. Huse, J. Opt. Soc. America, July, 1917- 



Plate. 

 Resolving power. 



Albumen. 

 12s 



Resolution. 

 81 



Process. 

 67 



Lantern. 

 62 



Medium 



speed. 



35 



High speed. 

 27 



See Nietz and Huse, J. Franklin Inst. March 3, 1918. 



* B. J. Almanac, see annual Almanac of British Journal of Photography. 



f B. J. refers to-British Journal of Photography. 



TABLE 376. — Reflection and Transmission by Photographic Plates 

 Plates used, Eastman 40, emulsion, 2637 ; for red, green, and blue light, W ratten filters 

 customarily used for 3-color work, see Wratten light filters,* Eastman Kodak Co. ; for 

 " actinic " data, average transmission of plate for a band of wave length corresponding to 

 the sensitivity curve of the plate was obtained by photographing the transmission of light 

 upon a plate of the same type. (McRae, R. C. Tolman, Journ. Opt. Soc. Amer., 20, 565, 

 1930.) 



For " Instruments and Methods used for Measuring Spectral Light Intensities by 

 Photography," see George R. Harrison, Journ. Opt. Soc. Amer., 19, 267, 1929. This 

 reference contains bibliography of subject matter. 



The Eberhard effect is due to the fact that when a heavily exposed area of an emulsion 

 is being developed, a large quantity of soluble bromide is set free which acts as a restrainer 

 and slows the development of surrounding regions. 



Smithsonian Tables 



