Lip color diversity: An intricate study.

BACKGROUND: Lip investigations and characterizations in the literature are less prevalent than for skin, particularly on the topic of color diversity. However, as the consumer demand increases for a nude lip makeup result, that is, shades close to the bare lip color, the identification and modification of lip color is essential for the cosmetic industry. OBJECTIVE: The objective was to highlight lip color diversity among three ethnicities (Caucasian, African and Hispanic), through the use of a spectral color measurement device especially adapted to the lip area, and to consider lip color ethnic specificities and overlaps. MATERIALS AND METHODS: The inferior natural lip color was measured with a full-face hyperspectral imaging system, SpectraFace (Newtone Technologies, Lyon, France), on 410 healthy women aged 19 to 68 (Caucasian French, Caucasian American, African American, and Hispanic American women). A hierarchical ascending classification, was deployed to determine clusters based on the lip colorimetric parameters along two strategies to identify the best statistical analysis to preserve the lip color diversity. RESULTS: Lip color is a continuous color space, with great intra-ethnic and inter-ethnic diversity, especially for African American women in terms of chroma and lightness. Among the two strategies of data analysis, our two-step statistical clustering analysis yielded 11 groups (i.e., 11 lip tones), revealing an accurate representation of the scope of diversity, but also of the overlaps. CONCLUSION: The 11 lip tones/colors could potentially serve as target shades for the development of a more diverse and inclusive range of lip cosmetics, such as nude lipsticks.

Lip color measurement: A new hyperspectral imaging device.

INTRODUCTION: The lips are of significant interest among the facial features for self-perception and social interactions. Such perceptions could rely in part upon the contrast in color between the lips and the surrounding skin. In contrast to skin color, lip color ethnic diversity measurement provides a challenge and is less documented in the literature, most likely due primarily to challenges in measurement based upon the lip characteristics of size and contour. Accurate measurement and reproduction of lip color are essential to build strong cross-sectional knowledge about lip color. OBJECTIVE: This preliminary experiment of a large-scale project on lip and skin color was designed to assess accuracy in lip color measurement and recommend instruments and protocols for good measurement practice. METHODS: The study involved 19 healthy French Caucasian women. Their inferior and superior natural lip color was measured twice with three devices in order to extract the standard colorimetric parameters of lightness (L*), chroma (C*), and hue (h): the VISIA-CR® (high-resolution digital camera, Canfield Scientific Inc.); the spectrophotometer VS3200 (45°:0° spectrophotometer, MetaVue™ VS3200, X-Rite Inc.); and the SpectraFace® (new hyperspectral imaging system, Newtone Technologies). The intercomparison and color distribution between the different instruments and the measurement repeatability of each one were assessed. RESULTS: Our results showed a reliable and equivalent repeatability for the three tested instruments. Moreover, the three tools led to the same conclusion regarding lip color heterogeneity (lighter, redder, less yellow and more saturated inferior lip versus superior lip). Agreement between the SpectraFace® and the spectrophotometer measurements was higher, and the SpectraFace® allowed to identify three separated lip color typologies. CONCLUSION: In conclusion, the combination of imaging technology and hyperspectral measurement makes the SpectraFace® a useful tool to investigate lip color characterization and establish a large-scale cross-sectional knowledge study about lip color.

Influence of age and hormone replacement therapy on the functional properties of the lips.

AIMS: To investigate the influence of age and hormonal status on some functional properties of the lips of women. METHODS: Lips properties were measured and compared through four groups of women (young with normal menses, aged with normal menses, aged and menopaused, aged, menopaused receiving hormonal replacement therapy). The following parameters were recorded: sebum excretion rate on the forehead. On the lower lip: TEWL, mechanical damping, color, tactile acuity. Moreover, capacitance images of each lips were recorded and the mean capacitance measured. RESULTS: Changes in TEWL, mechanical damping and tactile acuity appear clearly linked to age while the increase in lip darkness could be due to hormones. Sebum excretion rate is also clearly linked to hormonal status. Surprisingly, no changes of lips capacitance were detected vs. age or hormonal status. This study confirms that upper lip is more hydrated than the lower one. CONCLUSION: Most of the parameters measured on the lips have similar variations than the same parameters measured on the skin. Only sebum and color appear being dependant on the hormonal status.

Development and validation of a new Skin Color Chart.

BACKGROUND: Age-induced skin color variations are of great importance and incite increasing demand for cosmetic products to improve the appearance. The evaluation by clinicians or estheticians of the efficacy of skin care products is particularly difficult and requires the help of color charts. PURPOSE: To standardize this kind of evaluation, we have developed a new Skin Color Chart. In contrast to other color charts, this new one represents true skin color without metamerism and covers almost all skin colors encountered around the world. This new instrument has been validated for both Asian and Caucasian skin complexion and sun spot color. METHOD: The new device used to record skin color, the Chromasphere, developed by L'Oréal, is briefly presented. All skin color measurements and the validation of each selected Color were performed under identical conditions, and then, absorption spectra of both skin and chart were compared using severe criteria. The first use and the validation of this Skin Color Chart were performed by dermatologists (two in China and one in France) in groups of about 40 women on sunspots and complexion color. RESULTS: Regarding repeatability (intraobserver agreement), the new Skin Color Chart showed very good statistical validation on complexion and sunspot color. The agreement between dermatologists, the reproducibility criterion, although not as good remained high. An example of the evaluation of the efficacy of a whitening product is given in order to illustrate the 'sensitivity' of this new device to evaluate very weak color variations. CONCLUSIONS: The new Skin Color Chart appears to be very useful and easy to use even by clinicians without training in color evaluation.