What is the line of demarcation in hair coloring?

The line of demarcation refers specifically to the visible line that appears when there is a distinction between hair that has been colored and new hair growth that has not been treated. As hair grows, the roots become evident, and this line signifies where the newly grown hair starts, contrasting with the previously colored strands. This line can be more prominent with certain hair colors or if a drastic color change has occurred, making it important for hairstylists to manage this appearance through techniques like blending or touch-ups. Recognizing and addressing the line of demarcation is crucial for maintaining a seamless, well-blended hair color, ensuring the overall look remains polished as the hair continues to grow.