92 PHOTOGRAPHIC PROCESSES. 



control. I have developed very fine negatives with 

 but two drops of ammonia for a 5 by 8 plate ; of 

 course the plate had plenty of time. It takes about 

 five minutes to 'develope a dry plate properly. If 

 you use the oxalate developer, use it on the same 

 theory as the pyro. Oxalate in the place of pyro. ; 

 iron in the place of ammonia ; only that you must 

 add the iron to the oxalate not the reverse* Oxa- 

 late gives the strength and iron the detail. If you 

 commence slow, you need not use any bromide in 

 either case. As bromide is only used to correct 

 over-exposure, it takes off part of time, the same 

 as when it is not washed out of the emulsion. Fix 

 in hypo, and wash as usual. 



LIST OP ARTICLES NEEDED. 



Washing box ; heating box, for melting and fil- 

 tering emulsion ; dipping thermometer ; oilsfcove ; 

 racks, for drying ; Swiss or Heinrich/s gelatine ; 

 Hartley's silver; ammonium bromide; pure car- 

 bonate of soda ; citric acid ; alcohol ; chrome alum ; 

 one quart pitcher ; one quart bowl ; half-gallon pit- 

 cher ; one gallon bowl ; several small pitchers, for 

 flowing ; silver knife or horn spatula get one at 

 any drug store. 



CLEANING AND PREPARING THE GLASS. 



Soak the glass in lye, well wash, and put into strong 

 nitric acid, and albumenise same as in the wet pro- 

 cess, using the albumen a little thicker. Do not 



