What method is typically used for coloring gray hair?

Permanent hair color is typically used for coloring gray hair because it provides full coverage and long-lasting results. Gray hair often has a coarser texture and may be more resistant to color absorption, which is why a permanent solution is preferred. Permanent hair color works by opening the hair cuticle and allowing the dye to penetrate the hair shaft, which ensures that the color is more durable and doesn't wash out easily, making it suitable for those looking to fully cover gray roots over an extended period.

On the other hand, temporary hair color is short-lived and would wash out in as little as one shampoo, making it insufficient for those wanting to cover gray hair completely. Semi-permanent hair color may also not provide the exact coverage needed for gray strands and typically fades faster than permanent color. Highlighting, while it can add dimension and lighten hair, does not directly address the issue of gray coverage, as it involves lightening selected sections of hair rather than providing an all-over color solution.