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HANDBOOK OF PHOTOGRAPHY 



the usual manner. The density of the various steps is then measured, and the den- 

 sities are plotted against the corresponding exposure in the form of the usual Z)-logio E 

 characteristic. Such a curve gives the sensitometric characteristics of the test film 

 under the specified processing conditions. 



The test strip is then processed in the intensifying bath, according to the conditions 

 required for the particular intensifier in question. After the strip has been dried, the 



Subpropor+i'onoil 

 'n+ensif icoi+fon 



Fig. 1.- 



log,oE log,oE lo3io^ 



-Characteristic curves of intensified materials for various types of intensifiers. 



densities of the various steps are again measured and plotted as a second D-logio E 

 curve. We thus have two density determinations for various exposed portions of the 

 test strip; one made before and one made after intensification. The characteristics 

 of the intensifier in altering the original density of the unintensified test strip may 



Originoil Density 



Fig. 2. — The characteristics of various types of intensifiers, plotted against the density of 

 the unintensified material. This type of curve shows the same characteristics as Fig. 1 , 

 although in a different form. 



then be interpreted from such a graphical plot. Figure 1 illustrates the Z)-logio E 

 characteristics of a test strip without intensification, as well as for three idealized types 

 of intensifiers. In curve A, represented by a proportional intensifier, all the densities 

 of the original negative are increased in the intensification process by the same per 

 cent. In curve B, the higher densities are increased a relatively greater amount than 

 the lower densities, whereas in curve C the lower densities receive greater intensifica- 

 tion than the higher densities. The desired characteristic of practically all intensifiers 



