What does the term "overlapping" refer to in hair coloring?

The term "overlapping" in hair coloring specifically refers to the practice of applying color onto previously colored hair. When a stylist overlaps color onto hair that has already been treated, it can lead to uneven color results or damage, as the previously colored hair may absorb the new color differently compared to the uncolored sections. This technique is often discussed in the context of maintaining hair color, as it's essential for hairdressers to be aware of how previous applications can affect the outcome of new color treatments.

While multiple colors can be applied simultaneously and foils can be used to separate colors, these processes do not directly relate to the concept of overlapping. Similarly, creating custom shades through mixing colors does not involve applying new color over existing color. Thus, understanding the implications of overlapping is crucial for achieving optimal results in hair coloring.