Image Analysis Tools to Quantify Visual Properties of Hair Fiber Assemblies 300 when applied to hair than lower refractive index oils. Likewise, we examined some very high refractive index polymers (1.70 to 1.90) and found that these greatly increased the amount of specular reflection from hair. Unfortunately, these polymers were not fit for consumer use due to their limited solubility in personal care solvents. Most likely, the optical mechanism responsible for such a phenomenon lies in the change of direction of light striking the hair surface when a film is present. A polymer with an index of refraction greater than hair would decrease the refracted angle relative to the normal. Therefore, one would expect the specular reflection band to become more concentrated, and thus greater in intensity, with higher refractive index materials. Diffraction: By formal definition, diffraction occurs when light travels through a small aperture resulting in divergence over a wider area or when light waves bend around an object. There are many examples of diffraction including prism effects, hologram patterns on DVDs, etc. In spectrometers, diffraction is often utilized to separate light into its individual wavelength components. Polychromatic light illuminates a reflective diffraction grating with periodically spaced rulings, resulting in the dispersion of light into its individual constituents. In hair, it was proposed that cuticles act like rulings in a grating, which diffract light and produce the Figure 2. Refraction of light upon entry into the hair fiber