Which base is recommended for color treatments on brunette hair?

For color treatments on brunette hair, using a cool blue or green base is recommended because these cool tones help to neutralize any unwanted warm undertones that may exist in brown hair. Brunette hair can sometimes show warmth, especially if it has been previously dyed or exposed to sun, leading to undesirable brassy or orange hues.

By incorporating a cool blue or green base into the color treatment, these hues counterbalance the warmth effectively, resulting in a more balanced and aesthetically pleasing color outcome. This technique is particularly important when aiming for cooler shades like ash browns or muted tones that can enhance the overall look.

In contrast, warm red or orange bases can enhance brassy tones, which is typically not desired on darker hair colors. Similarly, neutral yellow bases might not effectively address the warmth in brunette hair, and vivid purple tones, while beneficial in certain contexts such as toning blonde hair, might not provide the desired effect on brunette hair either.