i I J 2008 ANNUAL SCIENTIFIC SEMINAR 9.00E+o6 8.00E+o6 7.00E+o6 6.00E+o6 S.OOE+o6 4.00E+o6 3.00E+o6 ·· 2.00E+o6 1.00E+o6 O.OOE+oo 300 350 400 450 soo ,so 600 �[11111] Figure I Comparison of the fluorescence spectra of on-pigmented hair from individual #2 obtained at the excitation wavelength 320 nm and 12 inches from the root part with the spectrum of pure powder of3- hydroxykynurenine . Peak assignment: 395 nm -unidentified, 425 nm - N-fonnylkynurenine, 460 nm - kynurenine, and 495 nm - 3-hydroxykynurenine. 359 Hair coloration of the 11 unpigmented samples varied significantly in terms of the degree of yellowness. Likewise, the fluorescent properties of different hair tresses also varied significantly in terms of the tryptophan intensity at 356nm and the intensity in the 395-500 nm range. Quantitative measurements of coloration to determine the Yellowness Index (YI) revealed a linear correlation between YI and the ratio of fluorescence intensities l44o/h56, suggesting that the yellow coloration of the fibers is related to the degradation of tryptophan in the fiber. Finally, the rate of the tryptophan degradation for each individual sample was determined by evaluation of the fluorescence emission spectra at various positions along the length of the hair tresses from root to tip. The calculated rate of photo-decomposition was relatively fast for un-pigmented hair (8· 104 - 1.5· 10" 3 [day· 1] (as calculated for hair obtained from various individuals) and slower for pigmented hair. CONCLUSION Fluorescence of grey hair, in both un-pigmented and melanin pigmented fibers, is caused by tryptophan and its metabolic or photo-oxidation conversion products including chromophores such as N-formylkynurenine, kynurenine, and 3-hydroxykynurenine. Un-pigmented hair produces higher fluorescence intensity than pigmented hair. Yellow coloration of grey hair is related to tryptophan degradation. References: [l]- R.Crippa, V.Horak, G.Prota, P.Svoronos, and L.J.Wolfram, Chemistry of melanins, The Alkaloids, Vol.26, Chapter 6, p.253, Academic Press, 1989. [2] - B.Hollfelder, G.Blankenburg, L.J. Wolfram, and H.Hocker, Chemical and physical properties of pigmented and non-pigmented hair ("grey hair"), Int.J.Cosmet. Sci., 87-89 (1995).

360 JOURNAL OF COSMETIC SCIENCE WHAT COLOR IS COLORED HAIR? Peter Kaplan, Ph.D., Kongsheng Yang, K. McAllister and K. Ram Ramaprasad TRI/Princeton, 601 Prospect Avenue, P.O Box 625, Princeton, NJ 08542 Not only are the optics of color formation from uniformly dyed and naturally colored (by discrete melanosomes) different, but also the optical effects of damage on these hairs are different. To explore these differences, we study natural and dyed hair (both originally pigmented and originally de-pigmented) subject to a variety of sourc,es of damage. The primary measure is the angular dependence of the color of hair tresses wrapped around a cylinder under directional illumination. Mechanical damage has a distinct signature related to the accumulation of rough chipped cuticle edges. Color fading, from shampoo with or without UV produces different color shifts. The details of these changes are critical to the perception of the depth and vibrancy of color. The differences in optical signatures between originally pigmented and de-pigmented hair are relevant to consumers who use dye to cover their gray hairs. The research reported in this presentation is intended to explore the hypothesis that the vibrancy and quality of hair color is related to the color differences observed when viewing a hair style on a curved head. Most materials reflect color differently at each angle, in the optics and computer graphics literature, these differences are described using a wavelength dependent bi-radial distribution function 1 • In this work, we sample a limited portion of this function using tresses wrapped on a cylinder, a common geometry for viewing hair. Exploring a set of damage standards, in which both natural and dyed hair are exposed to UV, wash and mechanical damage, we find characteristic changes in color quality on damage. The details will be reviewed orally. Dyed hair shows considerably greater change on UV and wash dama.ge than natural hair. 1 K. Ward, F. Bertails, T-Y Kim, S.R. Marschner, M-P Cani, M.C. Lin, IEEE Trans. Vis. and Computer Graphics 13 :213 (2007).