Thermoluminescence analysis is a sensitive technique for studies of imperfections in insulators and in radiation dosimetry. Natural minerals, and many synthetic materials, are often spatially non-uniform in their optical emission and knowledge of such features is essential for modelling of the thermoluminescence processes. To quantify such problems a Photek photon imaging camera has been added to the Sussex TL system. Data show examples of (i) zones of high intensity emission, even when there are no obvious anomalies in the emission spectra; (ii) differences between the uniformity of radioluminescence and thermoluminescence; (iii) resolution of signals from multi-mineral mixtures, and (iv) evidence of discharging zones from pyroelectrics. Examples of such data are presented.