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Abstract
‘The properties of a wide range of polyhydroxy compounds as tanning developers have been investigated, these including substituted pyrogallols and substituted catechols as well as benzopyrilium and coumarin derivatives. The electron attracting character of the substituents was shown to be an important factor in the effectiveness of these compounds as tanning developers. The effects of substituents on the aerial oxidation of the developers was also investigated in addition to the pH dependence. The best photographic characteristics were obtained with a developer containing 4-methyl daphnetin and pyrogallol’.