SPECULAR REFLECTION IN HAIR 41 untreated 17 mg/g 61mg/g Figure 11. Images of untreated and sebum-tteated African hair. Exposure settings: fS, 1/13s. untreated 17 mg/g 61mg/g Figure 12. Image threshold of the images shown in Figure 11. See text for explanation. Untreated 17 mg/g 61 mg/g Table IV Quantification of Reflection Sites on African Hair Treated With Sebum Number of reflections 742 536 273 % Black 98.34 99.02 99.67 % White 1.66 0.98 0.33 bright white light that corresponds to the reflection centers. Image file types usually have a scale from O to 25 5 to represent the colors in the image, with O representing the darkest colors (black) and 25 5 the brightest (white). By isolating values that fall in the range from 225 to 250, we can look at the brightest reflections on an entirely black background (Figure 12), allowing us to count the total number of reflections.

42 A B JOURNAL OF COSMETIC SCIENCE I ,20 .e ! 100 f B O i. 60 :J 40 o+--------.------.--------.-----.----.-------1 0 40 --------------convex1Peak Peak2 convex Peak 3 60 Distance (mm) -----------------concave Peak4 --------------+----+---+-CODVCX Peak 5 -----------------------concave 160 140 I 120 .! ! 100 I 8 0 E so 40 20 20 40 60 80 100 Distance (mm) 100 120 120 140 Figure 13. Examples of hair with various types of curvature: (A) frizzy hair, (B) very curly hair, and (C) curly hair. Plots of luminance as a function of distance are provided for each hair type, where the outlined area in each image was used as the sampling area.