Black hair dye may fade differently on bleached hair compared to unbleached hair. When hair is bleached, it becomes more porous, which can make it more susceptible to color fading. This means that black hair dye may fade more quickly on bleached hair than on unbleached hair. Additionally, the resulting color may not be as vibrant as it would be on unbleached hair. However, the extent and speed of the fading will depend on several factors, including the quality of the hair dye used, the individual’s hair type, and their hair care routine.