What is a soap cap in hair coloring?

A soap cap refers specifically to a mixture that combines equal parts of a permanent hair color and shampoo. This technique is often used for color correction or to refresh previously colored hair while simultaneously cleansing it. By mixing the permanent color with shampoo, the hair color is not only applied but also slightly diluted, which allows for a gentler application. This method can help blend color regrowth with the ends of the hair, leading to a more harmonious overall appearance.

Using a soap cap can also minimize damage that might otherwise occur from applying a full-strength color. The shampoo acts as a buffer, allowing for easier distribution of the color throughout the hair, which can help achieve a more consistent shade. This method is particularly popular for clients looking for a lighter hue, making it a versatile choice in color treatments.

In contrast, the other options suggest various mixtures or methods that do not accurately represent what a soap cap is, thereby clarifying why the combination of equal parts of permanent color mixture and shampoo is the correct answer.