The effect of transition metal ion doping on the charge carrier dynamics in commercial TiO2 pigments has been investigated. The response to extended polychromatic irradiation was monitored by real-time measurements of microwave photoconductivity and photodielectric effects. In addition to intrinsic differences between the rutile and anatase polymorphs, shifts in the resonance frequency and quality factor of a tuned microwave cavity as a function of annealing, and foreign-ion incorporation provided a gauge of the influence of extrinsic trapping centres on photoactivity. Parallel luminescence studies revealed an extension in the lifetime of the emission band on doping, the energy associated with recombination being independent of the dopant ion.