What is an important consideration when applying hair color?

When applying hair color, avoiding the overlap of old color applications is crucial for several reasons. When color is applied over previously colored hair without taking care to avoid overlapping, it can lead to an uneven result. This is because hair that has been previously processed may absorb color differently compared to virgin hair. Overlapping can cause the already-colored hair to become excessively saturated, leading to an undesirable shade or even hair damage. Moreover, it can result in a darker hue at the roots while the ends may appear lighter, causing an uneven coloration.

Other considerations, while they may seem important, do not hold the same weight. For instance, applying color to dry hair is not typically necessary as many formulations are designed to work best on damp hair, promoting better absorption and even distribution. The choice of developer volume should be based on the desired results rather than a blanket statement to always use the highest. Lastly, while it's advised to mix brands cautiously due to possible incompatibility, there are circumstances where different brands can be safely combined if they are compatible and properly formulated for the intended use. Therefore, focusing on the avoidance of overlapping during color application is essential for achieving the best results.