15/70
Originally
developed by the Imax Corporation in 1970, this format
uses 70mm film run through the projector horizontally, so
that the width of the film is the height of the frame.
In all other LF and conventional formats, the film runs
vertically, so that the width of the film is the width
of the frame.
Each
frame is 15 perforations wide, hence 15/70. The area of
the frame is about 52mm high by 70mm wide (2 inches by
2.75 inches).
The
15/70 frame is almost nine times larger than the conventional
35mm frame (below) used in neighborhood movie theaters. It is
slightly less than twice as large as 8/70.
Although
Imax Corp. was long the exclusive maker of 15/70
projectors and cameras, other manufacturers now make 15/70 systems.