NOVEL ACID-TYPE HAIR COLOR TECHNOLOGY 39 "Permanent " acid-type Conventional acid-type Figure 5. Microscopic observation of a cross section of human hair dyed with the "permanent" acid-type and a conventional acid-type hair color. Both hair colors contained acid orange 7 (0.44%) and acid red 52 (0.15%). The "permanent" acid-type contained 0.5% A1Cl3 ·6H2O and 1.6% glycolic acid. 110 110 (A) Red fashion Shade (8) Brown for gray coverage � 100 -�- ■ -100 �� � 0 0 �- ' � I � ♦ C � C 90 C 90 � ·a, ·a, C ♦ C cu I cu .c .c 1.- 0 - 0 �� 0 80 0 80 u u :l 70 70 0 2 4 6 0 2 4 6 Times of wash Times of wash Figure 6. Color brightness and color longevity effect of (A) red fashion shade and (B) brown-for-gray coverage on Asian white hair. The closed square (■), diamond ( ♦ ), and triangle (.&) represent the color-changing ratio of "permanent" acid-type, conventional oxidative, and conventional acid-type hair colors, respectively. The color-changing ratio was evaluated by the following equation: Color changing ratio (%) = [dEwashec.l hai,} / [dEdyed hai,} x 100 where dEdyed hair and dEwashed hair represent dE immediately after dyeing and washing, respectively. In (A), the color brightness effect, which is represented by dEdyed hair' of novel acid-type, conventional oxidative, and conventional acid type, is 57.80, 31.35, and 48.44, respectively. In (B), the color brightness effect, which is represented by dEc.1yed hair• of novel acid-type, conventional oxidative, and conventional acid type is 44.52, 44.61 and 39.77, respectively.

40 JOURNAL OF COSMETIC SCIENCE tional oxidative hair color but that the color longevity effect was inferior to that of the oxidative hair color. The color brightness and color longevity effects of the "permanent" acid-type hair color were far better than those of conventional acid-type hair color despite the fact that the formulation of dye was the same as that of conventional acid-type hair color. The color longevity effect of the "permanent" acid-type hair color was slightly better than that of oxidative hair color. It is seen on Figure 6B that both the color brightness and color longevity effects of the conventional acid-type hair color was inferior to those of the conventional oxidative hair color. Both the color brightness and color longevity effects of the "permanent" acid-type hair color were improved to the same level as those of permanent (oxidative) hair color despite the fact that the formulation of dye was the same as that of conventional acid-type hair color. In Figure 7, color brightness and color longevity effects were tested by Caucasian brown hair sourced in East Europe. The test results (Figure 7) show that the "permanent" acid-type hair color has a preferable performance on human hair re­ gardless of race. The hair tresses dyed for 30 min were washed by conventional shampoo. The discolor­ ation by shampoo was evaluated by the radio of �E (Figure 8). The color change ratio of the "permanent" acid-type hair color was higher than that of the conventional acid­ type hair color and conventional oxidative hair color, indicating that the "permanent" � 0 :;:::::. � 0, C ·a, C co (.) 0 0 0 110 (A) Red fashion Shade 10ow� ♦- -♦ ♦ 90 �----. I - � l 80 ■ ----- 70 ■ 60 50 0 2 4 6 Times of wash 110 (B) Brown for gray coverage 100i\- '#- i--- 90 ' 0 :I.. :;:::::. � 0, C 80 ·a, C -� co (.) 0 70 0 0 60 ■----------- 50 0 2 4 6 Times of wash Figure 7. Color brightness and color longevity effect of (A) red fashion shade and (B) brown-for-gray coverage on Caucasian hair. The closed square (■), diamond ( ♦ ), and triangle ("-) represent the color­ changing ratio of "permanent" acid-type, conventional oxidative, and conventional acid-type hair color, respectively. The color changing ratio was evaluated by the following equation: Color changing ratio (%) = [LlEwashed hair} / [LlEdyed hair} x 100 where LlEdyed ha ir and LlEwashed hair represent LlE immediately after dyeing and washing, respectively. In (A) the color brightness effect, which is represented by LlEdyed hair, of novel acid-type, conventional oxidative, and conventional acid type is 14.67, 10.38, and 12.59, respectively. In (B), the color brightness effect, which is represented by LlEdyed hair, of novel acid-type, conventional oxidative, and conventional acid type is 14.66, 13.75, and 12.50, respectively.