Accurate measurements of hair luster on the head (HLH) in situ is not an easy task and no satisfactory method is available at this time.
A new instrumental analysis method called “Color Image Analysis” was developed in this study to overcome the problem. In this method, a ratio of mean brightness in the highlight and adjoining dark portion of the hair image is computed from blue and red color signals. The result was much improved correlation with visual observation, compared with formerly used goniophotometry, since our HLH data included elements of micro-surface condition, macro-state as well as color.
Using this method, effects of changes in the state of hair and usefullness of hair-care products were investigated. We obtained interesting results on the effects of hair-luster preparations and hair coloring. It was clear that our method could be used to accurately determine the difference in hair luster.