AUTOMATED DEVICE TO ASSESS HAIR SHINE 459 Reich/Robbins equation. The increase of the objective shine value in this case is mainly achieved by a reduction (-22%) of the half width of specular refl ection (HWspecular). This is accompanied by a slight reduction (-12%) of the integral specular refl ection (RS), which itself is more than compensated by a substantial decrease (-31%) of the integral diffuse refl ection (RD). In total, these changes add up to an increase in the objective shine value of 50%. The appropriateness of the equation of Reich/Robbins (eq. 1) has been correlated with eye-tracking investigations (5) of panelists assessing the shine of hair tresses mounted on Figure 4. Determination of combing values. To quantify the parallelism of a given hair tress, the entire object is divided into a defi ned number of vertical rows. At each position on a given row, the average hori- zontal intensity is calculated (upper panel). To assign a combing value to a given hair tress, vertical positions of iso-intensities (100%, 66%, 50%, 33%, and 25% of maximum intensity) of each individual row are de- termined (lower panel), and the means ± SDs of vertical position numbers for the respective iso-intensities from all rows are calculated. The combing value is determined as the mean of all standard deviations of the respective iso-intensities. The lower this value, the higher the parallelism of the hair fi bers.

JOURNAL OF COSMETIC SCIENCE 460 the carrier device. The equation defi nes that the higher the contrast between specular refl ection and its background, the higher the objective shine value. In fact, the eye-tracking data clearly demonstrate that panelists also preferentially focused on the area of highest contrast, i.e., the borders of the specular refl ection (data not shown). Thus, objective shine values calculated using the shine box, and subjective rankings of shine made by panelists, are mainly determined by contrast properties around the area of specular refl ection. Panel studies of hair care products can only give ranking results, comparing subjectively one product with another. As a consequence, although measurement of hair shine using the opsira Shine-Box gives quantitative parametric values, comparison of both methods is restricted to rankings. Among nine studies conducted side-by-side using panel assessment of hair care products (≥3 products tested, 2 tresses per product, 30 pan- elists each) and assessment using the Shine-Box, seven studies gave exactly the same rank- ing with both methods. An example of the results of one such study is given in Figure 6. In two studies the ranking of two products was different with both methods. Taking panel Figure 5. Increase in the objective shine value achieved with a leave-in hair care product on blond hair tresses (A), as well as the effect of treatment on the single components’ half-width of specular refl ection, integral specular refl ection, and integral diffuse refl ection (B). Figure 6. Correlation of objective shine values determined by the opsira Shine-Box and subjective shine values from panelist rankings. Peroxide-bleached hair tresses treated with different shampoos (two tresses per hair care product four shampoos in total) were assessed side-by-side using the opsira Shine-Box and a panel of 25 independent raters. In the panelist assessment, the tresses were presented in a randomized pair-wise order to the raters. Each tress was presented in different combinations with other tresses at least three times. Mean panel values depicted in the upper and lower panel were derived from the overall rankings. In the case of shine values determined by the opsira Shine-Box, high numeric values represent a higher objective shine. In contrast, higher numeric values of the mean panel values represent a lower subjective shine.