BOTANICAL PHOTOGRAPHY 



187 



Developer for bromide enlargements (Agfa). 



Ml 



Water 1,250 



Metol 



Sodium sulphite 



Hydrochinon 



Sodium carbonate 



Potassium bromide 



The time required for exposure and development depends upon 

 several factors, but, assuming that, with a good negative and Agfa 

 Velvet Cyco paper, 10 seconds is about right for the exposure, two 

 minutes will probably be the maximum time required for complete 

 development. Some papers will require much less exposure and some 

 will require more. 



Plain hypo hath. — Many prefer a plain hypo bath, because the addi- 

 tion of a hardener makes lantern slides and prints more difficult to 

 color. With this bath, we strongly recommend an acetic acid "short- 

 stop" — water with enough acetic acid to make it taste like a weak 

 vinegar — to be used between the developer and the hypo. About 10- 

 20 seconds is long enough. As developer is carried into the short-stop, 

 add a few drops of acetic acid occasionally to maintain the acidity. If 

 a lantern slide should not look bright and snappy as it comes from the 

 hypo, rock it in the acetic acid solution until it brightens. This bath is 

 good for plates, films, lantern slides, and papers. 



Metric Avoirdupois 



Water 1,000 c.c. (32 oz.) 



Hyposulphite of soda 250 g. ( 8 oz.) 



Acid-fixing a.nd hardening bath. — 



Metric Avoirdupois 



Water 1,000 c.c. (32 oz.) 



Hyposulphite of soda 250 g. (8 oz.) 



B 



Water 250 c.c. (8 oz.) 



Sulphite of soda 22 g. ( f oz.) 



Sulphuric acid 4 c.c. ( | oz.) 



Powdered chrome alum 15 g. ( | oz.) 



Pour B into A, stirring vigorously. This is then a one solution bath, 

 with a greenish color, which can be used repeatedly. It hardens the 



