The present paper describes the time resolved photoconductivity applied in fluid media to the study of ion photogeneration. In the first part, it is shown that this technique is a powerful alternative to the transient absorption spectroscopy for the determination of ion yield. By using external reference it is possible to determine accurate ion yields (error < 5%). The second part is a typical application on a three component system ketone/amine/bromocompound which is an efficient photoinitiating system. The bromocompound acts as a scavenger towards ketyl radical. This reaction leads to the recovery of the initial ketone and the generation of a new initiating species.