236 JOURNAL OF COSMETIC SCIENCE (a) 1.06E+06 9.06E+05 8.06E+05 7.00E+05 6.00E+05 5.06E+05 4.06E+05 3.06E+05 2.06E+05 1.06E+05 0.06E+06 306 unexposed unexposed: 145o/14,s = 0.77 ß : ---- , , •0 406 450 506 Wavelength (nm) (b) 1.20E+06 1.06E+06 Q- 8.06E+05 ._•- 6.06E+05 • 4.06E+05 2.06E+05 0.06E+06 330 30 mj,• ............................. unexposed: 14sdl4,s = 0.74 '• •:" '••.......,.. 30min: 1450/14,5=0.80 , i i i i 380 430 480 530 580 Wavelength (nm) 2.50E+06 (c) ß --, 1.50E+06 • 1.OOE+06 "5.06E+05 0.060E+06 30 min ,• .................. --,-....... unexposed: 14so/1415 = 0.81 ,,,= ............................... 30 min: 1450/1415 = 0.88 ,,,," '•,,•,,, 360 41 0 460 51 0 560 Wavelength (nm) Figure 7. The emission spectra of light-brown Caucasian hair, at excitation wavelengths of 290 nm (a), 320 nm (b), and 350 nm (c), before thermal exposure and after 30 min of treatment. Thermal treatment was administered at 164øC. Aa and Ab, which leads to a large change in chromaticity (AC). This is also reflected by large increases in the yellowness indices for these two types of hair, as well as for bleached hair. Pigmented hair, on the other hand, experienced small differences in yellowness.

EFFECT OF CURLING IRONS 237 (a) 7.00E+05 6.00E+05 • 5.00E+05 •" 4.00E+05 ,g • 3.00E+05 *' 2.00E+05 1.00E+05 O. OOE+ O0 unexposed unexposed: 145o/14•s = 0.83 30 min: 145o/14•s = 0.91 i , 400 450 5OO 550 Wavelength (rim) (b) 1.00E+06 9.00E+05 8.00E+05 7.00E+05 6.00E+05 5.00E+05 4.00E+05 3.00E+05 2.00E+05 1.00E+05 O.00E+00 330 30 min•.• .............................. unexposed: 145o/14•s = 0.78 "•',, ,,'•' •• ••..,,. ,,.. ...... 30 min: 145d14•s = 0.81 __,,,,,,,,///// •unxpos-...........'...........'"'"".... i i i i 380 430 480 530 580 Wavelength (rim) (c) 2.00E+06 1.80E+06 A 1.60E+05 Q. 1.40E+06 ,-- 1.20E+06 • 1.00E+06 • 8.00E+05 ß - 6.00E+05 -- 4.00E+05 2.00E+05 O.00E+00 unexposed unexposed: 145o/14•5 = 0.84 ,,,,,. 30 min: 145dl4•0.87=min ..................................... 4...• 30 i i i i 360 410 460 510 560 Wavelength (nm) Figure 8. The emission spectra of Asian hair, at excitation wavelengths of 290 nm (a), 320 nm (b), and 350 nm (c), before thermal exposure and after 30 rain of treatment. Thermal treatment was administered at 164øC.