PHOTOGRAPHIC PROCESSES. 91 



The ammonia is used for detail. The bromide is 

 used to correct over-exposure. Citric acid is used to 

 keep the pyro. from oxidising. 



FORMULA. FOR DEVELOPING. 



No. I. Pyrogallic acid, 3 grains. 

 Citric Acid, 1 grain. 

 Water, 1 ounce. 



No. II. Ammonium bromide, 48 grains. 

 Ammonia, 3 ounces. 

 Water, 3 ounces. 



Take enough of the pyro. solution in your deve- 

 loping tray to well cover the plate ; let it remain in 

 this solution for a few seconds ; put two or three 

 drops of the ammonia solution into your developing 

 cup ; pour pyro. solution out of dish into cup con- 

 taining ammonia, then pour contents of cup on to 

 the negative ; in a few seconds the image will begin 

 to appear. Repeat the operation of adding the 

 ammonia, drop by drop, until you get all the detail 

 out. 



Remember that the pyro. gives the strength : the 

 more pyro. the more strength; the less pyro. the less 

 strength. 



Ammonia gives the detail : the more time the less 

 ammonia. Therefore if you take plenty of time and 

 commence with very little ammonia, you will get a 

 fine negative. Always commence with not more 

 than 2 or 3 drops of ammonia solution, then, no 

 matter what the time is, you have the plate under 



