What is the main purpose of using a color filler in hair coloring?

The main purpose of using a color filler in hair coloring is to restore warmth and vibrancy before applying a new color. When hair has been previously colored, especially if it has been lightened or stripped of pigment, it can lose its natural undertones and appear dull or flat. A color filler helps to reintroduce these missing pigments, which ensures a more balanced and even application of the subsequent color.

By filling in these undertones, the color filler provides a better base for the new color, helping to prevent unwanted results such as uneven coloring or unexpected changes in hue. This is particularly important when going from a lighter hair color to a darker one or when transitioning between different color tones. In essence, using a color filler is a crucial step to achieve vibrant and consistent results in hair coloring processes.