JOURNAL OF COSMETIC SCIENCE 316 (14) “Twistometry: Measurement of Skin Elasticity” in Non-Invasive Methods and the Skin (CRC Press, Boca Raton, FL, 1995), pp. 319–328. (15) M. F. Ramirez, Measurements of subcutaneous adipose tissue using ultrasound images, Am. J. Phys. Antrop., 89(3), 347–357 (1992). (16) A. Bellissari, Sonographic measurement of adipose tissue, J. Diagn. Med. Sonogr., 9(1), 11–18 (1993). (17) G. Zomios, J. Bykowski, and N. Kollias, Skin melanin, hemoglobin and light scattering properties can be quantitatively assessed in vivo using refl ectance spettroscopy, J. Invest. Dermatol., 117, 1452–1457 (2001).

J. Cosmet. Sci., 62, 317–325 (May/June 2011) 317 Luster measurements of lips treated with lipstick formulations SANTOSH YADAV, NEVINE ISSA, DAVID STREULI, ROGER McMULLEN, and HANI FARES, International Specialty Products, 1361 Alps Road, Wayne, NJ 07470. Accepted for publication January 28, 2011. Presented at the Annual Scientifi c Seminar of the Society of Cosmetic Chemists, Uniondale, New York, June 3–4, 2010. Synopsis In this study, digital photography in combination with image analysis was used to measure the luster of several lipstick formulations containing varying amounts and types of polymers. A weighed amount of lipstick was applied to a mannequin’s lips and the mannequin was illuminated by a uniform beam of a white light source. Digital images of the mannequin were captured with a high-resolution camera and the images were analyzed using image analysis software. Luster analysis was performed using Stamm (LStamm) and Reich-Robbins (LR-R) luster parameters. Statistical analysis was performed on each luster parameter (LStamm and LR-R), peak height, and peak width. Peak heights for lipstick formulation containing 11% and 5% VP/eicosene copolymer were statistically different from those of the control. The LStamm and LR-R parameters for the treatment containing 11% VP/eicosene copolymer were statistically different from these of the control. Based on the results obtained in this study, we are able to determine whether a polymer is a good pigment dispersant and contributes to visually detected shine of a lipstick upon application. The methodology pre- sented in this paper could serve as a tool for investigators to screen their ingredients for shine in lipstick formulations. INTRODUCTION Lips are a predominant anatomical feature of mammals. They are made up of three to fi ve epithelial cell layers, in contrast to the rest of the face, which is made up of 16 epithelial layers on average. Lips form a border between the exterior skin of the face and the mucous membranes in the interior of the mouth. Lips have no hair follicles, sweat glands, or sebaceous glands. Most lipsticks are a dispersion of coloring matter in a blend of oils, fats, and waxes. They are used to impart an attractive color and appearance to lips (1). By using appropriate lipsticks, narrow lips can be made to appear wider, whereas broad sensual lips can be made to appear narrow. The color of lipstick is one of the major selling points. Color is imparted to the lips either by stain or through pigments. The depth of color and opacity of lipsticks can be var- ied. Lip luster (gloss, shine) is an important feature of lip appearance, and this attractive visual effect is a key consumer objective in the cosmetics market. Perception of lip luster is