A system is described for the projection, digitizing, and recording of photographed spark chamber tracks. A Slo‐Syn‐driven projector automatically frames the film and projects the tracks on a screen mounted in a precision commercial plotting board. A reticle projector, mounted on the plotting board pen holder, is manually positioned by means of the plotting board drive tapes which also drive the encoders of an accumulating digitizer system. A photoelectric gap counting device can be substituted as an alternate for one of these encoders. The all‐transistor digitizer system is equipped with manual switches for labeling of tracks, inserting frame numbers, etc., and has a versatile output format on seven hole paper tape. The paper tape with its track coordinate information is used as the input for computer programs designed to calculate the particle physics evidenced by the track.