EVALUATION OF SKIN COLOR 13 Table V Summary of Correlation Coefficients r Between the Three Areas. P is the Level of Significance. N.S. Indicates P 0.05 N u* P v* P L* P r Palm/Cheek: 99 0.14 N.S. 0.17 N.S. 0.28 0.01 r Palm/Forearm: 99 0.32 0.01 0.25 0.02 0.31 0.01 r Cheek/Forearm: 99 0.27 0.01 0.33 0.01 0.31 0.01 Table VI Orthogonal Rotation of Factors Variables ! 2 3 V! u* palm .647 -.484 -.034 V2 v* palm .518 .065 -.033 V3 L* palm .071 .825 -.041 V4 u* cheek .254 .175 .854 V5 v* cheek .531 .303 -.137 V6 L* cheek .216 .352 -.797 V7 u* inner forearm .774 .058 .170 V8 v* inner forearm .704 .301 .104 V9 L* inner forearm .197 .619 --.024 Explained Variance (%) 27.31 18.04 13.43 (Table IV) between u* and L* of the palm and u* and L* of the cheek which indicates the relatively large degree of light scattering in these skin areas. The weak correlations of either u* (redness) or v* (yellowness) index between the three investigated skin areas (Table V and VI) indicates that it is useless to measure the color of the inner forearm or palm as a basecolor for the facial prosthesis. The instrumental determination of skin color and conversion and preparation of a color recipe should be exerted directly on the facial skin. The development of a preferably spectrophotomet- ric instrument suitable for such an intricate situation is desirable for the near future. The distribution of skin colors in our population in relative units can be determined from our colorimetric data. 95% of the population is within a width of four standard deviations. For the cheek the width of this range amounts to AL* = 29.6 Au* = 13.6 Av* = 13.6 (Viz. table III). Absolute data can only be roughly derived assuming that the spectrophotometric values at 30-mm diameter correspond to visual perception of the skin. Then the mean and standard errors of the distribution of a skin pigmented similarly to the face amounts to L* -- 61.63 _+ 1.4 u* = 26.73 _+ 0.9 v* = 26.9 -+ 0.4. Climatic, physiological and ethnical factors will probably make i t necessary to modify these color data, before it will be applicable in the artificial cosmetic replication of facial skin. Such work is in progress. ACKNOWLEDGEMENTS Thanks are due to P. Padmos, Ph.D. and F. W. Billmeyer, Jr., Ph.D., for their suggestions and discussions concerning to the measuring method, to Mr. R. Kroeze

14 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS s.c.d. from Borg-Warner Chemicals, for his valuable cooperation during the spectro- photometric measurement, to Miss A. van Hoogen for typing the manuscript, to Mr. H. Leydsman for the construction of the constant force balance and to Mr. Chr. Lingeman for preparing the illustrations. REFERENCE (1) T. O. Aina, S. M. Wright, and E. Pullen-Warner, The reproduction of skin color and texture in facial prostheses for negro patients,.]. Prosthet. Dent., 39, 74-79 (1978). (2) L. Fine, J. E. Robinson, G. W. Barnhart, and L. Karl, New method for coloring facial prostheses, .]. Prosthet. Dent., 39, 643-649 (1978). (3) E. A. Edwards and S. Q. Duntley, The pigments and color of living human skin, Am..]. Anat., 65, 1-32 (1939). (4) W. R. Buckley and F. Grum, The measurement of skin color, Spectrophotometric t•chnique,J. Soc. Cos. Chem., 15, 79-85 (1964). (5) J. S. Weiner, A Spectrophotometer for measurement of skin colour, Man, 253, 152-153 (November 1951). (6) G. W. Lasker, Photoelectric measurement of skin color in a Mexican Mestizo population, J. Phys. Anthropol., 12, 115-122 (1954). (7) J. F. Lontz, J. W. Schweiger, and A. W. Burger, Standards ofcolormatching, general concepts jSr pigment selection. Presented at the first international symposium on facial prosthetics, Arnhem (1976). (8) F. W. Billmeyer, Cautions required in absolute color measurement with colorimeters, Official Digest, 34, 1333-1342 (1962). (9) A. Jarrett, ed., The Physiology and Pathophysiology of the Skin (Academic Press, London, 1973), pp. 683-686. (10) D. B. Judd and G. Wyszecki, Color in Business, Science and Industry (John Wiley and Sons, New York, 1975)pp. 201-202. (11) G. W. Haupt and F. L. Douglas, Chromaticities of Lovibond glasses, J. Opt. Soc. Am., 37, 172 (1974). (12) G. W. Haupt, J. C. Schleter and K. L. Eckerle, The ideal Lovibond color system j$r ½IE standard illuminants A en C shown in three colorimetric systems (U.S. Natl. Bur. Std., TN-716, 1972). (13) R. S. Hunter, The Measurement of Appearance (John Wiley and Sons, New York, 1975), pp. 300-305. (14) M.J.M. Brand-Koolen, Factoranalyse in het sociologisch onde•zoek. Explicatie en evaluatie van enige modelien, Diss. Leiden (1972). (15) Wesp, 1Vaarlijk eenvoudig statistisch Pakket. Door L.Th. van der Welle, et al. Rekencentrum- publicatie 8, Groningen (1977). (16) A. R. Robertson, The CIE 1976 Color-Difference Formula, Color Research and Application, 2, 7-11 (1977). (17) R. S. Hunter, The Measurement of Appearance (John Wiley and Sons, New York, 1975), p. 203.