Methods are provided for authenticating a value article that includes a luminescent material. An exciting light source, an optical filter, a photodetector, a signal manipulation circuit, and an amplifier are provided. The luminescent material is exposed to light produced by the exciting light source. Radiation including light from the exciting light source and emitted radiation from the luminescent material is filtered using the optical filter to produce filtered radiation. The filtered radiation is detected using the photodetector to produce a detected radiation signal. The detected radiation signal is electronically manipulated using the signal manipulation circuit to reduce an effect of light from the exciting light source on an authentication determination based upon the detected radiation signal. The detected radiation signal is amplified with the amplifier after electronic manipulation to produce an amplified electronic signal. The amplified electronic signal or data derived therefrom is converted to an authentication output.