Iron ions photographic developer

If photographic materials are processed by developing solutions containing heavy metal ions, in particular iron(III) or copper ions, stains often occur. The addition of an inositolpolyphosphoric add to a color-developing solution complexes iron(III) ion, thereby preventing stain.86 In addition, aerial fog caused by heavy-metal ion catalyzed oxidation of the p-phenylenediamine color devel-... 

Any antidote for cyanide poisoning must be administered quickly. One antidote is sodium thiosulfate (the hypo used in the developing of photographic film). This substance converts the cyanide ion to a thiocyanate ion that does not bind to the iron of cytochrome oxidase. 

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