Dyeing and Discoloration of Human Hair Keratin Film Treated by Oxidative Hair Color

We have developed a preparation method of a translucent keratin film in addition to a nonanslucent film. The translucent keratin film was light brown and its surface was smooth by SEM observation. both films were treated with oxidative hair color reagents (dark brown and light brown), color deposit of translucent film was higher than that of the non-translucent film. Interestingly, the color can be easily ured from an absorption spectrum with a spectrophotometer. Thus, we dyed the translucent keratin film the dark brown color reagent under various conditions and analyzed the color deposit by a as a model system. The coloring was depending on the film thickness, the dyeing time, the ncubation temperature, and at lower pH. The formation of cysteic acid was significantly detected, similar to non-translucent keratin film. When the dyed films were immersed in distilled water and tap water, the discoloration by tap water was ster than that by distilled water. The addition of 0.5 mM CaCl2 to distilled water could induce the color fading. discoloration was also found when the dyed film was exposed to artificial light using a solar simulator. irradiation induced not only a significantly decrease of absorption around the 500 nm but also an increase absorption around the 400 nm, indicating a different hue of the dyed film. The translucent keratin film will be useful to evaluate conveniently the dyeing and discoloration of by dative hair dye reagents