Final answer:
A blue-violet-based haircolor helps neutralize unwanted warmth.
Step-by-step explanation:
The concentrate haircolor that helps neutralize unwanted warmth is a blue-violet-based haircolor. Blue-violet is opposite to yellow-orange on the color wheel, so it helps cancel out those warm tones. For example, if someone has brassy or orange tones in their hair, using a blue-violet-based haircolor will help neutralize those tones and achieve a cooler result.