Abstract: A method of photoluminence (PL) imaging of a series of silicon wafers, the method including the step of: utilizing incident illumination of a wavelength greater than 808 nm. The present invention further provides a method of analysing silicon semiconductor material utilising various illumination, camera and filter combinations. In some embodiments the PL response is captured by a MOSIR camera. In another embodiment a camera is used to capture the entire PL response and a long pass filter is applied to block a portion of the signal reaching the camera/detector.