What is the role of a filler in hair coloring?

The role of a filler in hair coloring is to equalize porosity and replace pigment. Filler products are essential tools in the hair coloring process, particularly when working with hair that has been previously lightened or damaged. These products help to restore the hair's ability to absorb color evenly and prevent potential issues such as patchiness or uneven tones.

When hair has varying levels of porosity, some sections may absorb color more quickly than others, leading to an unbalanced look. A filler addresses this by providing a base layer of color or pigments that fills in gaps in the hair structure, ensuring that the new color can deposit evenly across the entire strand. This is particularly important when switching from a lighter to a darker shade, as it helps the new color adhere properly and look uniform.

In addition to balancing porosity, fillers can also introduce warmth or depth to color formulations, which can be especially beneficial when performing corrective coloring or preparing the hair for vibrant color application.