This method is a combination of in vivo and in vitro measurement

This alternative method of determining sun protection does not require induction of a skin rash reaction.
HDRS is a combination of in vivo and in vitro measurements with excellent correlation with ISO 24444 for SPF and ISO24443 for UVA-PF values.
This is one of the few methods that takes into account the interactions of sunscreen formulation with the skin
ISO/CD 23698: HDRS- Cosmetics Sun protection test methods- Measurement of the Sunscreen Efficacy by Diffuse Reflectance Spectros