650 HANDBOOK OF PHOTOGRAPHY 



Stock Solution E 



Glacial acetic acid 4 oz. 



Plain water (warm) 24 ox. 



Copper sulphate (c.p.) 3 oz. 



Stock Solution F 



Ammonium chloride 12 oz. 



Plain water (warm) 24 oz. 



Stock Solution // 



Hypo crystals 16 oz. 



Warm water to make 32 oz. 



The working developer is made up by taking 



Stock solution A 2 parts 



Stock solution B 2 parts 



Distilled water 20 parts 



Satisfactory results could be obtained also by using the tanning developer formulas 

 given above. 



The time of development with the Duxochrome developer is of the order of 4 min. 

 at 70°F. when prints are made from normal negatives obtained directlj^ from the 

 original subject and processed to about gamma of unity or slightly less. When, 

 however, the printing is made from color-separation negatives of Kodachrome or Dufay 

 films, the required development time of the positive might be appreciably shorter 

 since the original color transparency^ is ordinarily very contrasty. The correct time 

 of development must be ascertained in such cases by trial. 



When dealing with very thin negatives an increase of contrast can be obtained by 

 increasing the strength of the developer such as, for instance, 



Stock solutions A 3 parts 



Stock solutions B 3 parts 



Water 20 parts 



In addition the time of development can also be appreciably increased. 



It is imperative that the Duxochrome developer be made up with distilled water. 

 The development of the three-color films must be carried out with as much uniformity 

 as possible, either by developing the three films all together with a fair amount of 

 uniform agitation or by developing each film individually in fresh developer for the 

 same length of time and same agitation. 



The degree of development cannot be judged by the appearance of the image as in 

 the case of bromide papers because the exposure was made through the celluloid sup- 

 port. Furthermore, under the darkroom safe light the images would appear appre- 

 ciably different because of the color pigments in the emulsion. 



Following development, the color films should be quickly passed, without rinsing, 

 into a stop bath as follows: 



Stock solution F 2 oz. 



Stock solution H 2 oz. 



Water 32 oz. 



The films can remain in this bath for only a few seconds, after which they should 

 be transferred to the fixing bath made up as follows : 



Stock solution H 4 oz. 



Stock solution C _. . J-2 oz. 



Water 4 oz. 



The time of fixing is about 10 min., and the films should be moved about occa- 

 sionally. The following operations can be now carried out in full daylight: 



After fixing, the color films should be washed in running water for about 3 min. 



