An instrumental approach enabling evaluation of efficacy of skin care products is disclosed. Common problems shared by existing methods include first the difficulty whether to test the entire human face, or just focus on the key locations (not determined yet)； the difficulty in conducting a repeatable test when human face is hard to fix on and changes between different persons； and how many different skin attributes to test for making a reliable and complete judgment. The instrumental approach of the process tests a sample at once to obtain all the information needed. It shows good repeatability and sensitivity. It yields necessary yet sufficient information in numbers.
