Abstract
It is a common experience that a makeup which forms a smooth, continuous film when applied on one person may form uneven, unattractive film on another subject. Formulating makeup which can provide perfectly uniform film, regardless the skin condition, remains an unanswered challenge to cosmetic formulators.
The purpose of this study was to investigate the reasons for the above difference and to find relationships between the uniformity of the film and the physical properties of the makeup foundation ingredients and the effects of microstructure of the skin surface.
Factor analysis of the experimental data indicated that the uniformity of the foundation film had most significant relationship with the evenness of the relief pattern shown by the skin surface replica. Three-dimensional measurements of the replica by a surface roughness meter established that the evenness of the rising portions of the skin surface was the main controlling factor in determining the uniformity of the film.
Relationship between the uniformity of the applied film and physical properties of the powder were investigated by determining the uniformity of the powder film applied on the skin or a positive replica. Reduction of the particle size of the powder and prevention of agglomeration were found to promote forming uniform films. A new surface treatment technique by fluoride coating effectively reduced surface activity of the powder, reduced the particle size and eliminated agglomeration. Using this technique and information from this research, we developed a novel makeup which proved to form very uniform film even on uneven skin surface.
