82 PHOTOGRAPHIC FACTS AND FORMULAS 
Pyrocatechin (Bothamley).— 
A. Pyrocatechin 10g 
Sodium sulphite, dry 40 ¢ 
Water 500 ccm 
B. Sodium carbonate, cryst. 100 g 
Water 500 ccm 
Time, 1 hour at' 18°C, (65°) F:). 
Pyro-soda (Claudy).— 
Sodium sulphite 3.9¢ 
Sodium carbonate 2.6¢ 
Pyro 13g 
Water 1000 ccm 
Pyro-soda (Harris).— 
Pyro lg 
Sodium sulphite, dry 3g 
Sodium carbonate, cryst. 12 ¢ 
Potassium metabisulphite 6.5 ¢ 
Water 1000 ccm 
Time, 10 to 15 minutes at 16° C. (60° F.). 
Pyro-soda (Munkman).— 
A. Pyro 100 g 
Potassium metabisulphite 25g 
Water 1000 ccm 
B. Sodium sulphite, dry 100 g 
Sodium carbonate, cryst. 100 g 
Water 2000 ccm 
For use, mix 1 part A, 1 part B and 8 parts water. Time: 
25 minutes at 18° to 21° C. (65° to 70° F.); 30 minutes at 
15° to 18°. C. (60° to 65° F.) ; 40 minutes at 13; toto 
(55° to 60° F.) ; 50 minutes at 10° to 13° C. (50° toga Bae 
If the developer be used at half the above strength, the times 
will be: 50 minutes, 1 hour, 80 minutes, and 100 minutes 
respectively for the above temperatures. 
154 er. 
616 gr. 
174 oz. 
3% oz. 
174 oz. 
90 gr. 
60 er. 
30 gr. 
48 oz. 
20 gr. 
60 gr. 
240 er. 
130 gr. 
40 oz. 
1 oz. 
Y4 oz. 
10 oz. 
1 oz. 
1 oz. 
20 oz. 
