HAIR VOLUME AND TEXTURE 349 Table V Experiments III and IV: Spearman Rank Correlation Coefficients (Rho) for Image Analysis vs Visual and Image Analysis vs "Visual + Feel" Panelist Evaluations Image analysis vs Relative Image analysis "visual + feel" volume change vs visual body body in test Experiment III 0.85 * 0.84' 3.0 Experiment IV 0.94** 0.71' 1.6 * p 0.001. ** p = 0.0001. by the two sexes. In each experiment, the women evaluated tresses from treatment B to have less body than the men rated them to have. The "visual q- feel" rating (of the women) was also lower than that for visual evaluation alone. This hair has a rough, dry feel that the women dislike. The men, however, do not seem to regard the rough feel as negatively as the women, and these men continue to assess the particulate-treated tresses as hair with good body. For example, for Experiment IV the statistical analysis of hair body ("visual + feel") ratings by men and women shows (p = 0.05): Women Men Most body D[ D* E E •/ F* B c I Least body B C* These data serve to emphasize: (i) the influence of hair texture on hair body assessment (ii) that the sex of the assessor may influence whether the textural component is per- ceived to enhance or diminish hair body, particularly when the hair volume change is small. EVALUATION OF TECHNIQUE TO DISCRIMINATE WITHIN A PRODUCT TYPE Finally, we conducted an experiment (Experiment V) to determine the sensitivity of the image analysis/hair body method to distinguish between formulations within a product type--in this case shampoos. The two shampoos chosen were: ß A conditioning shampoo, A, consisting of anionic surfactant and insoluble silicone suspended with an acylating suspending agent ß A conditioning shampoo, B, consisting of anionic surfactant with paraffin wax sus- pended with an acylating agent Six tresses of equivalent weight (3.5 g) and initial combability were selected, and were then repeatedly washed with either shampoo A or shampoo B (three tresses per shampoo treatment). After five washes the hair body of the tresses was determined using the described image analysis method. The data showed that the hair washed with Shampoo B occupied a larger volume, i.e., had more body, than that shampooed with Shampoo A (ANOVA: 90% confidence level, p = 0.056). Similar results were found after ten

350 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS washes (ANOVA: 90% confidence level, p = 0.068). Combining the results, it is concluded that these two shampoos alter hair body differently (98% probability, p = 0.018) and that Shampoo B-washed tresses have more hair body than tresses washed with Shampoo A. The tresses were also evaluated by an expert panel. They judged the hair treated with Shampoo B to be cleaner, fuller, and "drier" and to have more body than the A-treated hair. The latter tresses were assessed to be more conditioned, softer, and slightly limp. Friedman analysis of the data showed the two treatments significantly different at 99% confidence level. This experiment demonstrates the utility of the image analysis technique for instru- mentally evaluating, and differentiating between, hair body effects of shampoos, that is, after treatments that alter hair fiber surfaces in a relatively small manner. These two shampoos differ basically in the use of paraffin wax (B) and silicone (A) as the active conditioning materials. This image analysis hair body technique essentially assesses the different surface effects of these two compounds delivered from a shampoo. Hence this experiment provides further evidence of the utility of this technique for the cosmetic chemist. CONCLUSIONS A method has been developed to quantify hair body in terms of volume changes in tresses measured either via planimetry or by image analysis. For large volume differences (eight- and fourfold respectively), hair body can be evaluated as hair volume irrespective of textural changes. We have shown, too, that the image analysis technique can dis- tinguish between formulations within a product type (shampoos) and that the data agree with expert panel (subjective) evaluations. We have also presented panelist data that indicate a textural component is sometimes a part of self-assessment of hair body. As hair increases in curvature, hair body and hair volume generally increase. However, there are individual preferences and limitations to curvature changes as the kinky region of curvature is approached. One limitation in the correlation of the image analysis technique with panelists' evaluation of hair body occurs if the hair is extremely curly (black Afro-American hair). Hair texture may also play a role in body evaluations, particularly when the relative volume differences between treatments is small (approx- imately 1.6-fcld or less). We conclude that image analysis is a valid technique to assess hair body of hair samples that encompass a wide range of volume and textural differ- ences. REFERENCES (1) M. L. Garcia and Jose Diaz, Combability measurements on human hair, J. Sac. Cosmet. Chem., 27, 379-398 (1976). (2) C. R. Robbins and C. Reich, Prediction of hair assembly characteristics from single-fiber properties. Part II. The relationship of fiber curvature, friction, stiffness, and diameter to combing behavior, J. Sac. Cosmet. Chem., 37, 141-158 (1986). (3) P. Hough, J. E. Hey, and W. S. Tolgyesi, Hair body, J. Sac. Cosmet. Chem. 27, 571-578 (1976). (4) C. R. Robbins and G. V. Scott, Prediction of hair assembly characteristics from single fiber prop- erties,J. Sac. Cosmet. Chem., 29, 783-792 (1978). (5) D. L. Wedderburn and J. K. Prall, Hair product evaluation: From laboratory bench to consumer and back again, J. Sac. Cosmet. Chem., 24, 561-576 (1973).