ELEMENTARY PHOTO-MICROGRAPHY. 103 



Four drams of A and four drams of B, with five 

 drops of 10% solution of potassium bromide, are 

 taken for a quarter-plate. 



For lantern slides the writer finds that hydro- 

 kinone is the most generally convenient. It may 

 be made up as follows : 



HYDROKINONE DEVELOPER. 



A. 



Hydrokinone . . . . 80 grains. 



Potassium bromide . . 15 



Sodium sulphite . . . . I ounce. 



Water . . . . . . 10 ounces. 



B. 



Sodium hydrate .V .. 50 grains. 



Water . . . . . . 10 ounces. 



Equal parts of A and B are taken to make one 

 ounce of developer. 



Hydrokinone is a developer that answers equally 

 well with ordinary plates, lantern plates, and 

 bromide prints ; and after the beginner has ob- 

 tained some proficiency, he may find it a conveni- 

 ence to have only one developer instead of several. 



Rodinal, kachin, metol, and numerous other 

 developers recently placed in the market can be 

 tried after mastering development with the simple 

 standard developers previously mentioned. 



