Boram’s latest research, titled “Brightness and Hue Judgment of Dyed Hair Color,” has been featured in the prestigious journal, Acta Psychologica. This insightful study unveils the psychological principles behind how individuals perceive and categorize dyed hair colors. Boram discovered that people typically assess hair brightness based on a power function of .7 times the L* (The Lightness of CIE1976L*a*b*) value of the hair. Furthermore, she highlighted a perceptual shift, notably in the context of brown hair, which is often regarded as a baseline color. Her findings offer a numerical method for enhancing digital hair dye services, paving the way for more accurate and personalized color selection tools.
This study aims to investigate human hair color perception through two empirical studies in the context of colored hair. The preliminary study was intended to establish a numerical representation of perceptually meaningful brightness levels. It identified that the brightness level was proportional to the power of 0.766 of L*. In the visual assessment, participants (N = 47) categorized 246 hair color samples into eight color hue groups aligned with the Munsell system. Hue judgment was conducted by visually comparing dyed hair tresses with natural black hair. Based on the L*, a*, and b* values of hair tresses and visual assessments thereof, we observed the ranges of hue categories for hair color alongside the brightness levels. Additionally, the differences between the Munsell hue names and the assessment results were compared. Predominantly influenced by the dark brown hair color, the neutral orientation was shifted to the first quadrant of the a*-b* plane. The study contributes to an understanding of human hair color perception and provides insights into color categorization and labeling, especially when the context is confined.