The structure of the reduced form of the dye can be represented by the general formula: ##STR1## wherein R1 represents a member selected from the group consisting of aryl groups having up to 14 carbon atoms and containing from 1 to 5 electrons withdrawing substituents, alkyl groups having {TAIL ~ up to 4 carbon atoms} and containing one or more electron withdrawing groups, certain electron withdrawing groups containing a ##STR2## moiety, and certain electron withdrawing groups containing {HEAD ~ a NH moiety} 
The structure of the reduced form of the dye can be represented by the general formula : # # STR1 # # wherein R1 represents a member selected from the group consisting of aryl groups having up to 14 carbon atoms and containing from 1 to 5 electrons withdrawing substituents , alkyl groups having { TAIL ~ up to 4 carbon atoms } and containing one or more electron withdrawing groups , certain electron withdrawing groups containing a # # STR2 # # moiety , and certain electron withdrawing groups containing { HEAD ~ a NH moiety }
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