JOURNAL OF COSMETIC SCIENCE 204 work could also be done to characterize the impact of oily formulations to describe the gloss impact on the histogram analysis. CONCLUSIONS The results obtained from the in vitro testing on skin tone color cards, and the in vivo screening study and image analysis of the panelists before and after application of the test skin creams provides evidence of improved radiance (as defi ned by the increased normal distribution parameters of brightness values) due to the presence of effect pigments in the formula. Uncoated natural mica provided no measureable benefi t for brightness, leading to the conclusion that the interaction of light with the pearlescent titanium dioxide fi lm in the three pearlescent effect pigments (natural mica, synthetic fl uorphlogopite, and borosilicate) is the contributor of the measurable increases in radiance. Relative to the other effect pigments, bismuth oxychloride (Product E) provided the smallest increase in brightening and the smallest change in histogram standard deviation and skewness. However, in comparison to the control formulation, the bismuth oxychloride test product was shown to provide a radiance increase. Evaluation of the color changes to the panelists’ skin after the application of the various test creams was a necessary step in this method of evaluating radiance. The gloss map images were created from pixel brightness values, gray-scale values that are combinations of lightness and color parameters in the original photographs, so it becomes necessary to study the behavior of the skin color with the application of the effect pigments. Sepa- rately observing the color in the in vivo testing ensures the increases in the gloss map analysis for radiance is due to lightness increases of the skin rather than chroma or color increases. Results from the in vitro colorimetry data demonstrate an increase in lightness of a simulated skin tone from the use of the pearlescent effect pigments that correlates to the Chroma Meter data in the in vivo testing. In additiona, the four effect pigment types tested demonstrated a color balancing to the skin tone in both the in vivo image analysis and the in vitro simulated skin tone drawdown, demonstrating that the radiance of the effect pigments applied to the skin is reducing the contribution of the red and yellow skin tone component (as defi ned by CIELab reductions of a* and b* values). While all four pearlescent effect pigment types tested contributed to this color adjustment, the ti- tanium dioxide coated natural mica and synthetic fl uorphlogopite pigments provide the greatest relative color adjustment and lightness increases. The in vivo panelist’s images proved necessary in the overall assessment of skin radiance since comparison of the histograms of the brightness values of the skin needed the three dimensionality of a panelist’s facial morphology. The histogram analysis showed that the application of the effect pigments in the creams provided an increase in brightness overall while creating a more contrasted skin, providing more range of light to darker areas of the skin with the increase in the standard deviation of the histograms. Also the histogram analysis shows that the addition of effect pigments did not make the skin appear glossy or oily. Compared to the control formula and the uncoated natural mica, all of the effect pigment technologies provided a measurable radiance benefi t when applied to the skin or in vitro testing. Creams formulated with small-particle-size pearlescent pigments can benefi t from the optical improvements provided by these pigments, and future work could be conducted to correlate the easily measured luster values based on multiangle

ENHANCING SKIN RADIANCE THROUGH THE USE OF EFFECT PIGMENTS 205 spectrophotometers on lacquer drawdowns to the more complicated in vivo image-based histogram analysis. REFERENCES (1) G.E. Uzunian and O.V. Dueva, The Impact of Skin Tone on the Color Generated by Effect Pigments. (Society of Cosmetic Chemists Annual Scientifi c Seminar, New Orleans, Louisiana, 2001). (2) L. Armanini, Basic Optics and Pearlescent Pigments. Paint Coatings Ind., 5(8), (1989). (3) A. Matsubara, Differences in the surface and subsurface refl ection characteristics of facial skin by age group. Skin Res. Technol., 18, 29–35 (2012). (4) G. Martin-Langrand, B. Beaufrere-Seron, R. Korichi, M. Neveu, and S. Schnebert, Facial and Skin Ra- diance: new Indexes. International Federation of Societies of Cosmetic Chemists, 28th Congress, Paris (2014). (5) N. Lunau, S. Bielfeldt, M. Seise, and K. Wilhelm, New method to assess soft focus parameters on living skin: How does it compare to visual lay person rating of skin radiance? International Federation of Societies of Cosmetic Chemists, 28th Congress, Paris (2014). (6) J.V. Koleske, Ed., Paint and Coating Testing Manual, 15th Ed. (ASTM International, 2012). (7) A. Matsubara, Z. Liang, Y. Sato, K. Uchikawa, Analysis of human perception of facial skin radiance by means of image histogram parameters of surface and subsurface refl ections from the skin. Skin Res. Tech- nol., 18, 265–271 (2012).