TABLE 603.— FORMULAS FOR DEVELOPERS 563 



In the determination of the values given in Table 604, developing solutions made up 

 according to the following formulas were used (temperature, 20° C) : 



Developer A : 



Monomethyl para-aminophenol sulfate * 2.0 grams 



Sodium sulfite (anhydrous) 50.0 " 



Hydroquinone 4.0 " 



Sodium carbonate (anhydrous) 6.0 " 



Potassium bromide .75 " 



Air-free distilled water to make 1.0 liter 



Developer B : 



Monomethyl para-aminophenol sulfate * 2.0 grams 



Sodium sulfite (anhydrous) 80.0 " 



Hydroquinone 4.0 " 



Borax 4.0 " 



Potassium bromide .5 " 



Air-free distilled water to make 1.0 liter 



Developer C : 



Water, about 125°F (50°C) 500.0 cc 



Monomethyl para-aminophenol sulfate * 2.2 grams 



Sodium sulfite (anhydrous) 96.0 " 



Hydroquinone 8.8 



Sodium carbonate, monohydrated 56.0 " 



Potassium bromide 5.0 



Air-free distilled water to make 1.0 liter 



* Sold under such trade names as Metol, Elon, Rhodol, and Pictol. 



TABLE 604.— SENSITOMETRIC CONSTANTS OF TYPE PLATES AND FILM 



Reciprocal 

 inertia * Speed 



Material Developer 7^ t y = y 00 /2 t y =1.0 (.Si) (Se) 



Motion-picture films 



Fast panchromatic B 1.30 10.2 21.5 2300 400 



Medium-speed panchromatic . . . B 1.70 9.8 13.0 1700 250 



Fine-grain panchromatic B 2.00 10.8 10.8 600 100 



Positive (regular) C 3.35 1.5 .9 25 



Positive (fine-grain) C 4.30 1.4 .7 5 



Sheet films and plates 



Fast panchromatic A 1.45 2.6 5.2 2500 500 



Fast orthochromatic A 1.50 2.0 4.2 1700 400 



Medium-speed panchromatic ..A 1.50 3.6 6.3 840 200 



Medium-speed orthochromatic . . A 1.25 2.7 9.9 850 200 



Blue-sensitive A 1.35 2.7 5.7 430 100 



Amateur roll films 



Fast panchromatic A 1.28 2.9 6.6 2500 400 



Fast orthochromatic A 1.25 2.2 5.7 1300 200 



Fine-grain panchromatic A 2.50 5.5 4.2 400 100 



Process films and plates 



Panchromatic C 6.90 3.3 .8 60 



Orthochromatic C 5.00 2.00 .7 60 



Blue-sensitive C 4.00 2.7 1.7 35 



* St — 10/i, where »' is the inertia value at 7 = 1.0. Reciprocal inertia was originally proposed by 

 Hurter and Driffield as a sensitometric measure of the speed of photographic materials. It bears no 

 direct relation to their effective speed as determined by camera exposures, however. It is useful for 

 comparing different types of materials which have no common basis of application in practice. 



SMITHSONIAN PHYSICAL TABLES 



