CHAPTER VIII. 

 SOLUTIONS FOR PHOTOGRAPHIC OPERATIONS. 



1st. To develop Gelatine Bromide Plates. The Pyrogallol 

 or " Pyro " Solution : 



Take 



Sodic Sulphite 4 ounces 



Water to about. 7 ounces r dissolve 



Make slightly acid with sulphurous acid. Then pour into a 

 a Commercial one ounce bottle of Pyro. Make up to nine 

 ounces and filter. 



Label the bottle " Pyro 10 per cent. 10 minims=l grain 

 pyro." Or better : 



Take 



Potassic M eta-Bisulphite*. % ounce, avoir. 



Water to about 7 ounces 



This will dissolve easily, especially if the salt is pounded ; then 

 pour into a bottle of Pyro as above and label as above, having 

 made up to nine ounces. 



Or, lastly : just before using make a sufficient quantity of 

 water acid with citric acid, and with that water make a solu- 

 lution of four grains of pyro to each ounce of acid water. This 

 will constitute one-half of the measure of what will be called 

 a " Normal Developer." 



The writer uses and recommends the Potassic salt formula. 

 But solution's known as " Sulpho- Pyrogallol " are sold, pre- 

 pared more or less according to the formula of Mr. H. B. 

 Berkeley, the originator of the compound, and these solutions 

 are usually good. As before, 10 minims of the solution=l 

 grain of pyro. 



* A patent salt to be obtained from The Scovill & Adams Co. 



