Abstract: A method and apparatus for controlling the positioning of a filmstrip in a film scanning gate using signal states derived from a pair of spaced film sprocket holes or perforation ("perf") sensors on either side of the film scanning gate in conjunction with line scan counts and filmstrip drive, stepper motor half-step counts. The filmstrip is advanced by the stepper motor in a pre-scan operation through the film scanning gate for line scanning the image frames at a low resolution and advanced in the reverse direction back into the film scanning gate for high resolution scanning in a main-scan operation. A line scan array of line scan counts and half-step counts as well as first and second perf arrays of half-step counts and perf sensor states are generated in the pre-scan operation. Image frame borders are located in the pre-scan operation as border line scan counts and correlated in the line scan array to the half step counts to go to in the main-scan.