The major conservation issue related to historic textiles dyed with early synthetic dyes is poor colorfastness to light and washing. The objective of this study was to obtain useful information for the conservation of such textiles through dye analysis and colorfastness testing. Silk crepe fabrics, which could be dated to the Meiji or the Taisho era, were examined. The dye class was identified through several tests including solvent extraction. A total of 133 sections of different colors were analyzed : acid dyes and basic dyes were detected in 46 sections and 25 sections, respectively. Next, 12 fabric specimens of different dye classes were subjected to light exposure and cleaning treatments. Remarkable fading was observed after light exposure in some of the fabric specimens dyed with basic dyes. Aqueous cleaning treatments induced serious color changes and/or staining due to bleeding in many of the fabric specimens, depending on the dye and dye class used, formulation of cleaning solution, and temperature. The results suggest that identifying dye classes used in a textile may be effective in predicting the properties of the dye or the dyed textile and may be useful for the appropriate care of the textile.