Visual cues for moisture perception of facial skin: a pilot study on the effects of enhancing high-spatial-frequency components of skin lightness to decrease perceived moisture levels in young Asian observers.

Facial skin texture provides crucial visual cues that reflect an individual's impressions and health conditions. In this study, we focused on the visual attribute of "moisture" and investigated which visual cues influenced skin moisture perception. The stimuli consisted of images from three facial areas (the whole face, cheek, and eyebrow areas) with and without makeup under two camera angles. The participants rated the presented stimuli on three visual attributes (moisture, glossiness, and attractiveness) via a five-point scale. The results from Experiment 1 revealed correlations between the ratings and histogram statistics of each channel in the CIELAB color space, with variations depending on the conditions and facial regions. A negative correlation was observed between cheek moisture perception and the variance in the L ^∗ channel. We subsequently obtained similar ratings by enhancing the high-spatial-frequency components of skin lightness for simulated skin conditions (Experiment 2) and for images depicting different skin conditions resulting from variations in post-cleansing skincare or base makeup (Experiment 3). These experiments confirmed that perceived moisture and attractiveness decreased, whereas perceived glossiness increased; these findings were correlated with images that were simulated via image processing to reduce the perceived moisture level. These findings indicated that the high-spatial-frequency components of skin lightness could be visual cues for determining the decrease in perceived moisture level.