MEASUREMENT OF HAIR LUSTER 297 4 Standard FMClI _L first second third fourth Figure 3. Average color-difference values obtained after sequential treatments in more damaged dark- brown hair tress. Treatments: standard and PQ7 Natura formulations. Quintuplicate measurements. D65 illuminant. 10 ø viewing angle. 5 x 10-mm viewing aperture. Reference tress: damaged dark-brown hair tress treated with ethyl ether/8 h. FMCII system. . • 3 internal reference I external reference • I I n ethcorn s+nl s+n2 s+n3 treatments Figure 4. Average color-difference values obtained after sequential treatments in black hair sample using external and internal references. Sample B3. Treatments: n (Neutrox © conditioner), ethcom (ethanol com- mercial/40 min), s + nl (]•lseve © shampoo + Neutrox©/first wash), s + n2 (]•lseve © shampoo + Neutrox©/ second wash), s + n3 (Elseve © shampoo + Neutrox©/third wash). Results of ten measurements. D65 illuminant. 10 ø viewing angle. 5 x 10-mm viewing aperture. Internal reference: ethanol PA/8 h treatment (fourth reading). External reference X = 3.27, Y = 3.32, Z = 3.23. FMCII system.

298 JOURNAL OF COSMETIC SCIENCE Table VII Statistical Analysis of Color Difference (DE) Data Obtained Using External Reference for CIELAB and FMCII Systems Treatment Sample Equations DE m S2R DE•4 S2T Ethanol B1 0.65 0.09 PA/8 h B2 CIELAB 1.31 0.32 0.89 1.30 B3 0.73 0.03 Ethanol B1 1.76 0.77 PA/8 h B2 FMCII 3.30 0.94 2.30 7.57 B3 1.18 0.40 B1 0.84 0.07 Commercial alcohol B2 (a) CIELAB 0.43 0.03 0.61 0.39 B2 (b) 0.46 0.04 B3 0.70 0.08 B1 2.98 O.43 Commercial alcohol B2 (a) FMCII 1.12 0.68 2.14 9.52 B2 (b) 1.89 0.44 B3 3.10 0.82 5 Neutrox © conditioner 6 Neutrox © conditioner B1 B2 B3 B4 B5 B1 B2 B4 B5 B3-fw? 7 shampoo + Neutrox © B3-sw?? B3-tw??? B3-fw? 8 shampoo + Neutrox © B3-sw?? B3-tw??? 1.95 0.27 2.94 O.25 CIELAB 0.75 0.05 1.58 8.29 1.53 0.09 1.78 0.16 4.21 1.23 FMCII 6.11 1.04 3.40 33.8 3.21 0.61 1.59 0.79 1.01 0.23 CIELAB 2.32 0.16 1.92 6.34 2.45 0.23 3.13 0.81 FMCII 5.01 0.82 4.44 13.09 5.20 O.99 DE m = average color difference among a set of ten measurements DE N = average color difference among the samples S2R = variance within sample S2T = variance among the samples. ?fw (first wash) ??sw (second wash) •'??tw (third wash). Operating conditions: horizontal sample position, D65 illuminant, 10 ø viewing angle, 5 x 10-mm viewing aperture, and adapted holder. Sets of ten measurements. Black hair samples (B1, B2, B3, B4, and B5). External reference: FMCII (X = 3.27, Y = 3.32, and Z = 3.23) and CIELAB (L* = 21.04, a* = 1.76, and b* = 1.58). diffuse reflectance data of a set of ten measurements for the alcohol-treated tress, as the one that presented the lower estimated standard deviation in color values. The data used as external reference were L* = 21.04, a* = 1.76, and b* = 1.58 (CIELAB) and X = 3.27, Y = 3.32, and Z = 3.23 (FMCII), for all samples. Figure 4 shows the average DE values (FMCII) obtained after sequential treatments in sample B3, using the external and the internal reference. Internal reference data for sample B3 were obtained from ethanol commercial/40-min treatment (sixth reading) for