Surface Color and Dyeing Amount of Natural Hair Dyeing Using Cochineal

This study analyzed the effects of mordants (alum, red clay, and salt) and dyeing temperatures (20°C, 40°C, 50°C, 60°C) on the natural dyeing of hair using cochineal. Hair samples were dyed according to combinations of each mordant and dyeing temperature, and the colors were measured using the CIE Lab* color space. The dye uptake was quantified using the K/S value. The experimental results showed that compared to the raw samples, the L*value decreased and the a* value increased under all dyeing conditions, indicating a more vivid color. At 20°C with alum, the L*value was 70.01, the a* value was 18.34, and the K/S value was 21.91, demonstrating the highest dye uptake. Red clay and salt also exhibited significant dye uptake with K/S values of 22.54 and 22.87, respectively. At 40°C with alum, the L*value decreased to 61.03, while the K/S value increased to 31.14. The K/S values for alum continued to rise at 50°C and 60°C, reaching 35.14 and 35.46, respectively. In contrast, red clay and salt showed relatively lower K/S values, but there was a trend of improved dye uptake with increasing dyeing temperatures. In conclusion, the combination of mordants and dyeing temperatures significantly affects dye uptake and color in natural hair dyeing with cochineal. Notably, using alum achieves high dye uptake. This study provides foundational data that can contribute to the optimization of natural dyeing and suggests the need for further research on combinations with various natural dyes and changes in the physical properties of hair after dyeing.