What coloring technique adds dimension to a solid brown by incorporating mild contrast?

The technique that adds dimension to a solid brown by incorporating mild contrast is brown on brown. This method involves using various shades of brown that are slightly lighter or darker than the base color, creating a more dynamic and multidimensional appearance without introducing the stark contrast that can occur with highlights or lowlights. It achieves subtle depth by enhancing the natural richness of brown hair, allowing it to reflect light differently and appear more vibrant.

Other techniques, like highlights, typically involve applying significantly lighter shades to create notable contrast, while lowlighting involves using darker shades to add depth but may not align with the desired mild contrast. Ombre involves a gradient effect where one color transitions to another, often leading to more extreme changes in tone. Brown on brown specifically focuses on enhancing the existing color with close hues, making it the optimal choice for adding dimension in a soft, harmonious way.