The invention relates to a system (1) for detecting image parameters during the exposure of films (2), especially radiographic films. The object of the invention is to provide a system which makes itpossible to simply and rapidly obtain optimally exposed images. To this end the system (1) has a detector element (3) which can be removably disposed on a film (2) and which carries out resolved detection of the radiation (4) incident upon the film (2) during exposure or the radiation (4) transmitted by the film, and therefrom generates a signal from which image parameters resulting from the current film exposure can be derived.