Modern hair treatments have to fulfill technical requirements and high emotional demands. While data on hair combing, tensile strength or fatigue testing are common to support technical claims, the market success of a product is essentially determined by fulfilling those emotional characteristics that are claimed in the advertisement.
In hair care, these emotional aspects are determined mainly by feel and appearance. Both of these parameters are difficult to assay directly by objective methods; they must be scored by sensory assessment and can be supported by a combination of various technical investigations.
In this study, the appearance of hair tresses was evaluated by color measurements, fiber tensile strength and keratin degradation parameters. The type of damage selected for testing purposes was irradiation by ultraviolet/visible (UV/VIS) light, simulating the sun.