Abstract: A time-resolved photographic analysis device is capable of analyzing for the presence of fluorescent radiation, particularly in a diagnostic sample. The apparatus comprises a light source for emitting exciting pulses as directed onto the sample. A camera is provided which is focused on the sample with the camera continually exposed to the sample. A chopper device is used in conjunction with the camera to prevent exposure of the photographic film in the camera to background fluorescence generated by miscellaneous components in the sample. Fluorescent labels, if present in the sample, are designed to fluoresce over considerably longer periods than the background fluorescence. A device is provided to coordinate the operation of the chopper device with the rate of flashing of the light source to ensure that the photographic film is only exposed to fluorescent radiation which would be generated by a fluorescent label in the sample being analyzed.