ST 257:1998 : For Motion-Picture Film (35-mm) — Stereoscopic Prints with Vertically Positioned Subframes — Projectable Image Areas
The Society of Motion Picture and Television Engineers eBooks · 1998
This standard specifies the maximum dimensions of the film image area intended for projection from a 35-mm motion-picture film using vertically positioned subframes for stereoscopic projection, and the placement of this area relative to the perforations and the reference edge of the film.