The invention relates to a method for the authentication of a security feature, containing an anti-Stokes shift luminescent material, wherein the wavelength of an electromagnetic emission is shorter than the wavelength of absorbed electromagnetic excitation radiation. The method comprises a calibration mode and a test mode. In the calibration mode, the excitation of multiple calibration patterns occurs at least in a rise phase and in a fall phase. The test mode includes the excitation of the security feature to be tested, the detecting of the emission response at a first check time (Ʈon) and at a second check time (Ʈoff), the determining of the gradient of the detected emission response, and the classifying of the security feature to be tested. The invention also relates to an assembly for the authentication of a security document having a security feature.