In order to elucidate photo-fading mechanism of indoaniline type dye forming color photographic image, photo-fading products in degassed ethanol solutions of model cyan dye with carbonyl compounds were identified. The used model cyan dyes were 2-chloro-N-(4-diethylamino-phenyl)-pnaphthoquinone monoimine (Cyan Dye 1) and N-(4-diethylamino-phenyl)-p-naphthoquinone monoimine (Cyan Dye 2). Separation of products and preparation of samples for NMR and mass measurements were carried out in an all degassed system. The product in Cyan Dye 2 solutions was identified as leuco form by addition of two hydrogen atoms to Cyan Dye 2 and 4-(4-diethylamino-phenyl)-amino-1-naphthol. The product in Cyan Dye 1 solutions was a salt of the same compound as the one in Cyan Dye 2 solutions with hydrochloric acid. During photo-fading of Cyan Dye 1 solutions, absorption spectra shifted to short wave-length gradually and it was confirmed that the blue shift resulted from dechlorination. Reaction mechanism was also examined and it was estimated that reactive species for dechlorination was a radical intermediate which was produced by addition of one hydrogen atom to azomethine group of Cyan Dye 1 by ketyl radical of carbonyl compound.