90 PHOTOGRAPHIC PROCESSES. 



To DEVELOP. 



Any developer that will work on any plate will 

 work on mine the same. But I claim that all 

 published developers given by dry plate factories are 

 right if the exposure is. But unless the exposure is 

 right, or nearly so, a failure is almost sure to occur. 

 My plan of developing, while I use the same chemi- 

 cals, is on a different theory, making the developer 

 suit any exposure, no matter how long. I claim that 

 it is impossible for any one to so accurately judge the 

 time needed as to suit a standard developer, but must 

 make the developer to suit any exposure, and by the 

 following plan you can take any number of plates 

 and nob know the time of exposure or amouut of light 

 on subject at time of exposure, and if there is plenty 

 of time, no matter how much, you can make a nice 

 negative by this plan of developing. In the first 

 place I will give the theory of development, as there 

 will be, no doubt, some of you that do not under- 

 stand it. 



. Pyrogallic acid is used to give strength to the 

 negative, and should be used according to the 

 amount of silver used in the emulsion. The smaller 

 the quantity of silver the smaller the quantity of 

 pyro. The more silver the more pyro. If more pyro. 

 is used than should be for the amount of silver, there 

 will be green fog ; if the proportion is right, the 

 plates will be clear in the shadows and no green 

 fog. 



