What type of brush is best for applying color to hair?

The flat brush is the best choice for applying color to hair due to its design, which allows for even and precise application of hair color. A flat brush typically has a wide, flat surface that can cover a larger area of hair efficiently, making it ideal for techniques such as balayage or all-over color application. This type of brush also allows for better control when parting the hair and applying the dye close to the roots, ensuring a thorough and uniform distribution of color.

In contrast, a round brush is primarily used for styling and creating volume rather than for applying color. A wide-tooth comb is excellent for detangling but is not suitable for the application of color as it does not hold or distribute hair dye effectively. A spoolie brush is designed for grooming eyebrows and lashes, not for applying color to hair. Therefore, the flat brush stands out as the best tool for this specific task in hair coloring.