IOO THE A B C OF PHOTO - MICROGRAPHY 



been in continuous use by classes of students 

 during all the succeeding sessions and are in 

 good condition at the present time. Finally, 

 it is no more costly than any of the ordinary 

 papers that are inferior to it for our purpose. 

 Its price is somewhat higher than these, but 

 this is more than offset by the cost of gold 

 used in toning the latter that is, where gold 

 is used unfortunately too often omitted, to 

 the entire ruin of the prints in point of per- 

 manency. The directions for printing and 

 developing, which accompany each package, 

 are so simple and efficient as to require no 

 additions here. They cannot be improved 

 upon, and the formula for metol-quinol devel- 

 oper seems to be perfect. Pure blacks and 

 whites, with soft gray half-tones, may be de- 

 pended upon from good negatives by its use. 

 Some subjects are decidedly improved by 

 printing in browns, sepias or reds. All of 

 these tones may be obtained by using the 

 same developer greatly diluted, to which a 

 few grains of ammonia carbonate should be 

 added. Long printing and still longer devel- 

 opment are required in these cases. I am not 

 prepared to give more extended directions for 

 these at present, not having done enough 

 work by this printing method to render 



