TECHNIQUE OF DEVELOPMENT 377 



The solution of diethyl p-phenylenediamine hydrochloride does not keep well, 

 hence it should be made up only a short time before use. 



6. Wash 



7. Bleach in the same formula as used for step 3 



8. Wash 



9. Fix in a hypo solution free from acids and sulphites as they bleach many of the 

 colors formed. A plain hypo bath of 20 to 30 per cent strength is suitable. 



10. Wash, and dry as usual. 



Extensions and variations of this process are used at present in experimental color 

 processes. Accordingly, there is considerable activity in this field and new color 

 formers, formulas, and processing methods appear imminent. 



Bibliography 



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 Parker, H., and J. I. Crabtree: Rapid Processing Methods, Communication 577, Eastman Research 



Laboratories. See also Am. Phot., March, 1936, p. 142; February, 1936, p. 67. 

 English, F. L.: Some Factors Affecting Grain Size, Am. Phot., May, 1937, p. 305. 

 Murray, H. D., and D. A. Spencer: The Addition of Silver Iron, Reactants to Organic Developing 



Solutions, Phot. J., July, 1937, p. 458. 

 Evans, R. M., and W. T. Hanson Jr.: Photographic Development and the Latent Image, Phot. 



J., August, 1937, p. 497. See also Communication 615 from the Eastman Research Laboratories. 

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Size, Phot. J., April, 1938, p. 192. 

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