Analyzing the Laser-Light Reflection from Human Hair Fibers Part 1: Light Components Underlying the Goniophotometric Curves and Fiber Cuticle Angles

The study analyzed laser-light reflection from human hair fibers using a multichannel goniophotometer, focusing on goniophotometric curves and cuticle angles across different hair types: brown and blonde Caucasian, and black Asian hair. It identified three types of reflected light: specular, diffuse, and internal, each described by a Gaussian distribution. The research found that hair color influenced the relative intensities of these light fractions, with black hair having a higher cuticle angle than brown and blonde hair. The width of the specular reflection peak decreased with lighter hair color, indicating that specular reflection originated near the hair surface. The study also noted that diffuse reflection peaks varied along the hair length, suggesting grooming damage, while internal reflection peaks in blonde hair were linked to its layered structure. These findings provided insights into the connection between hair surface morphology and light scattering, with implications for understanding hair luster and damage.