What is the recommended application process for touching up dark brown regrowth on light brown hair?

Applying color to the new growth only is the recommended approach for touching up dark brown regrowth on light brown hair. This technique is designed to create a seamless blend between the newly colored roots and the previously colored hair, ensuring that the transition appears natural. By focusing the application solely on the regrowth, you help prevent overlap onto the lighter strands, which could lead to undesired results such as darkening of the previously light brown hair or creating an uneven color effect.

This method also helps maintain the integrity of the previously colored hair, minimizing damage caused by repeated coloring. It's important to ensure that the timing of the application is carefully managed to avoid over-processing the previously colored sections.

In contrast, applying color to all hair would likely result in a stronger color effect and could lead to uneven coloring and unnecessary damage to the lighter strands. Mixing with a lighter shade could lighten the dark brown, but it may not effectively address the regrowth without causing inconsistency. Finally, using a bleaching technique is unnecessary for simply touching up regrowth, as it could further lighten areas that should remain dark brown, leading to an inconsistent look. Hence, focusing only on the new growth is the most effective and least damaging approach for this situation.