Abstract
Commercial makeup can enhance beauty when used on youthful skin. But when the same makeup is applied to aged skin, the result is often artificial and unnatural-looking. To find the cause of this phenomenon, we investigated the optical properties of skin and discovered that they strongly correlate with microtopography of the dermal surface. We learned that lateral diffusion of light on the skin surface is a key contributor to its optical qualities, and that this diffusion is strongly influenced by the condition of the microtopography. Further studies resulted in the discovery of an important optical parameter which we termed “Lateral Diffusion Index” (LDI). Youthful skin, with its more distinct and uniform pattern of microrelief, was found to possess a higher LDI value than does aged skin, with its flatter and more irregular pattern of microrelief. We then confirmed the practical application of our discovery by incorporating specially designed powdered fiber (300μm nylon fiber) into an experimental makeup to optimize light diffusion characteristics and substantially increase the LDI value of aged skin. Comparison studies demonstrated this new makeup to be more effective than traditional makeup in making aged skin appear more naturally alive and vibrant.
