Developing beauty-enhancing makeup by controlling light reflected from skin (II) – a makeup foundation producing an optimal reflectance dip on skin
Spectral reflection curves of human skin generally show a characteristic dip in the 500–600 nm range. This ‘dip’ is unique for each person, and is believed to be caused by the spectral absorption of blood. We investigated the spectral reflectance of human skin and discovered a very interesting correlation between the area of the reflectance dip and L* value (lightness of the skin). The standard area of reflectance dip (Ads) is defined and calculated from the correlation we discovered. The actual area of reflectance dip (ADa) is calculated from the spectral reflection curve. The ratio of ADa and ADs was found to be a very useful optical parameter for skin complexion perception. By artificially creating different optical environments and varying ADa/ADs from 10 to 200%, we found that skin appeared more beautiful when ADa/ADs was in the 100–125% range. We therefore considered methods for applying these results into the development of cosmetic products. Investigation and testing of many different pigments resulted in the development of specially-designed powdered fiber with a #-shaped cross section dyed magenta. An experimental foundation with this powdered fiber produced a clear reflectance dip by raising reflectance in the short and long wavelength ranges. ADa/ADs increased from 49 to 107% without reducing lightness when this makeup foundation was applied on sallow skin.
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Document Type: Abstract
R&D Laboratories, POLA Chemical Industries, Inc., 27-1, Takashimadai, Kanagawa-ku, Yokohama 221-0833, Japan,
Product Planning Division, POLA Cosmetics, Inc., 2-2-3, Nishi-gotanda, Shinagawa-ku, Tokyo 141-8523, Japan
Publication date: August 1, 2007