Abstract: An x-ray microfilm reader includes a microcomputer control system for controlling film loading, unloading and searching for a particular frame, as well as controlling exposure times for full-size reproductions ("blow backs") of the x-ray images. The x-ray microfilm is contained in a cartridge which is inserted into a cartridge station of the microfilm reader. When the user depresses an INDEX key, the control system automatically causes the microfilm to be withdrawn from the cartridge and wound onto a takeup reel until the first frame is aligned at a film gate. By entering a numerical value through a keyboard and then actuating a SEARCH switch, the user causes the control system to automatically drive the film until the selected frame is aligned at the film gate. The control system controls operating speeds of the drive motor as a function of the distance between the current frame and the desired frame, so that the microfilm is stopped at the proper frame without undershoot or overshoot.