title: Luster measurements of lips treated with lipstick formulations.
abstract: 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 (L(Stamm)) and Reich-Robbins (L(R-R)) luster parameters. Statistical analysis was performed on each luster parameter (L(Stamm) and L(R-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 L(Stamm) and L(R-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 presented in this paper could serve as a tool for investigators to screen their ingredients for shine in lipstick formulations.
authors.affiliation: International Specialty Products, Wayne, NJ 07470, USA.
authors.forename: Santosh
authors.initials: S
authors.lastname: Yadav
authors.forename: Nevine
authors.initials: N
authors.lastname: Issa
authors.forename: David
authors.initials: D
authors.lastname: Streuli
authors.forename: Roger
authors.initials: R
authors.lastname: McMullen
authors.forename: Hani
authors.initials: H
authors.lastname: Fares
mesh_terms: D003358:Cosmetics; D006801:Humans; D008046:Lip
chemical_list: D003358:Cosmetics