Optical - Release Print   

16mm optical sound is never very good, although with good transfer techniques and calibrated equipment it may be an acceptable mono playback system.  Although rarely used in professional theatrical presentation, 16mm projectors may be found throughout the world.  A 16mm optical print is the last truly international presentation medium. In North America 16mm may be the only form of film presentation in schools, universities and community centres so most Hollywood films are released in this format as well.
1KHz sine tone as captured by 16mm optical film