This International Standard specifies basic technical characteristics for magnetic sound test films used for checking, adjusting and measuring 70 mm motionpicture projector sound systems and sound reproduction channels of motion-picture installations. This International Standard includes specifications for test films intended for checking, adjusting and measuring of: a) azimuth of the magnetic head gaps (azimuth alignment test film; see table 1); b) output level balance of several motion-picture projectors or systems and interchannel balance on each projector or system (signal level test film; see table 2); c) frequency response of the sound reproduction channels (multi-frequency test film; see tables 3 and 4); d) non-uniformity in velocity of film travel (flutter) (flutter test film; see table 5).