Abstract: Dental x-ray film is properly aligned with the x-ray beam utilizing a plurality of infrared emitters and detectors that are positioned circumferentially about the path of the x-ray beam. A reflecting surface whose plane is parallel with the plane of the x-ray film holder and integral therewith can be positioned parallel to the plurality of emitters and sensors by repositioning until the sensors receive a predetermined reflective response. Each sensor activates an indicator light seen on a display and when all the lights in a bank of lights are activated alignment is achieved. The output of the sensors can also be summed and when the sum output reaches a predetermined value an oscillator is triggered thus creating an audible tone indicating proper alignment.