Method for measuring the UV protection effect or infrared protection effect of an aqueous composition containing an ultraviolet absorber or an infrared blocking agent, and a sample preparation device for measurement

摘要

An object is to measure absorbance of aqueous cosmetic materials that have not heretofore been studied for absorbance measurement, and particularly to form a uniform layer of thin film in order to ensure accurate measurement without causing these aqueous cosmetic materials, which are O/W emulsions, to undergo phase separation during measurement. As a means for achieving the foregoing, an absorbance measurement method is provided, wherein an absorbent aqueous composition is applied on the surface of a substrate, which surface has been plasma treated, arc-discharge treated, or corona-discharge treated, to achieve a contact angle with pure water of 0 to 70.0 degrees, and the applied absorbent aqueous composition is measured for absorbance.