TECHNIQUE OF DEVELOPMENT 



371 



Fine-grain Developers. — Borax developers of the type discussed and listed for 

 motion-picture negatives are considered fine-grain developers. The grain is not so 

 fine as that which can be produced with some other types of formulas. As noted 

 in the general discussion of fine-grain development, a wide range of additions to various 

 basic types has been attempted, so much so that no attempt will be made to cover the 

 entire range of constituents and concentrations. Another limitation to completeness 

 in this case is the fact that for commercial reasons the formulas of some of the success- 

 ful fine-grain developers have not been published. 



The fact should be reiterated that overexposure and high values of gamma both 

 tend, within normal limits of work, to increase graininess of the final result. Much 

 of the value of fine-grain technique can be lost by inattention to such details of expo- 

 sure and processing. 



Paraphenylenediamine is the reducer around which has centered many of the 

 attempts to produce particularly fine-grain images. Used with no other reducer in 

 weakly alkaline solution, such as that produced by sulphite, the graininess is equal to 

 or better than any other yet demonstrated. The effective emulsion speed is lower 

 than with more active developers of the borax type. This speed loss has been obviated 

 or reduced by the addition of a second reducer. Glycine has been used in this role in 

 one series of formulas. 



Table VIII. — Paraphenylenediamine Developers 



Sodium sulphite (anhydrous) 

 p-Phenylenediamine (base) . . 



Glycine 



Water to 



No. 19 



Metric 



90 g. 

 10 g. 



2g. 



1 1. 



Avoirdupois 



12 oz. 



1 oz. 145 gr. 



115 gr. 



1 gal. 



Range 



Metric 



45-90 g. 



6-12 g. 



0-12 g. 



1 1. 



Avoirdupois 



6-12 oz. 

 350 gr.-l oz. 260 gr. 

 0-1 oz. 260 gr. 

 1 gal. 



Developers for X Rays. — For normal development of X-ray films an active con- 

 trasty developer is desired. A rather concentrated developer is usually used to 

 obtain the needed long-life characteristics, and this is accompanied with relatively high 

 bromide content to keep fog down. 



On occasion. X-ray developer has been used as a nearly universal developer in some 

 laboratories, where it is the one developer always on hand. This practice is not to be 



Table IX. — Developer for X-ray Film 



No. 20 



Metric 



Rhodol (nietol or Elon) 



Sodium sulphite (anhydrous) 



Hydroquinone 



Sodium carbonate (monohydrated) 



Potassium bromide 



Water to make 



5.0 g. 

 60.0 g. 



7.5 g. 

 50.0 g. 



4.5 g. 



1 1. 



Avoirdupois 



290 gr. 



8 oz. 



1 oz. 

 6 oz. 290 gr. 

 260 gr. 



1 gal. 



Metric 



2.0- 5 . g. 

 45.0-105 g. 



7.5- 10 g. 

 45 - 60 g. 



4.0- 6.0 g. 

 1 1. 



Avoirdupois 



1 17-290 gr. 



6- 13 oz. 



1- 1 oz. 145 gr. 

 ■ 6- 8 oz. 

 232-350 gr. 

 1 gal. 



