Is it advisable to overlap during a hair color retouch?

During a hair color retouch, it is advisable to avoid overlapping color on previously colored hair. Overlapping can lead to hair damage because the previously colored areas may have already undergone a chemical process that has altered their structure. When new color or bleach is applied over these areas, it can result in excessive processing, leading to dryness, breakage, or even unwanted color results.

It's important to apply the color only to the new growth to ensure that the hair is treated carefully and to maintain its integrity. This technique ensures that the hair retains its health while achieving an even and balanced color throughout. Proper technique during a retouch not only safeguards the condition of the hair but also achieves the desired color effect by preventing color banding or inconsistent tones.