In vitro SPF, UVA PF and Critical Wavelength with pre-irradiation

This test consists in evaluating the Sun Protection Factor (SPF), UVA Protection Factor (UVAPF) and Critical Wavelength (CW) which expresses the sun protection level of a sunscreen product through the full UV spectrum, using an adequate substrate on which the product has been spread and measured by means of a spectrophotometric method. To take into account any potential photo-unstability, the product is irradiated before measurement.