Chapter 15 513 The reason for this occurrence likely resides in the many factors that can contribute to the outcome of these measurements. By means of illustration, technical shine possesses a sizable dependence on hair color. Higher pigmentation within fibers reduces the likelihood of light penetrating into the hair and reflecting from the underside of the cuticle structure. This occurrence produces a shoulder on the shine band and a subsequent decrease in the ratio of specular to diffuse reflectance. Thus, as shown in Figure 13, darker hair (lower L) gives rise to higher technical shine results. This outcome does not seem unreasonable, as one perhaps considers the especially shiny appearance of heavily pigmented Asian hair. This said, extremely straight styles are prevalent in such cultures, and it becomes apparent that fiber alignment will have a considerable contribution to the interaction of light and a hair array. Moreover, this factor is not captured in conventional hair array shine measurements, as tresses are manually aligned and anchored on a cylindrical holder (see Chapter 9). Figure 13. Dependance of technical shine results on hair color
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