Which factor is crucial for determining how long to leave a color on the hair?

The duration for which hair color should be left on is primarily determined by the desired shade and hair type. Different shades may require varying processing times to achieve the intended results; for instance, lighter colors or fashion shades generally need a longer time to develop properly compared to darker or more neutral tones. Additionally, different hair types, such as fine, medium, or coarse hair, can influence how the hair absorbs color and the speed at which it processes. Fine hair might lift and take on color more quickly, whereas coarse hair may require more time for the hair cuticles to fully absorb the color. Understanding these factors ensures the stylist can achieve the desired results safely and effectively.