Filmed in 3-D and DeLuxe Color and presented in CinemaScope, it is notable as the only U.S. feature film made in 3-D between Revenge of the Creature, which was released in the spring of 1955 and marked the end of the 1950s 3-D movie fad in the U.S., and The Bubble, which premiered in late 1966 and introduced the economical “over-and-under” single-strip format used by most of the 3-D films of the 1970s and 1980s.
Like the feature-length 3-D films of the 1950s when they were originally released, it was projected by the polarized light method and viewed through gray Polaroid filters in viewers which, according to the film’s poster, were “scientifically designed by master craftsmen!” Most theaters, however, presented it “flat”, in 2-D.
Although it is widely believed to have been filmed in Stereovision, Bob Furmanek, who oversaw the 2016 restoration, says this is a myth. It was shot full-frame with the original NaturalVision cameras used on Bwana Devil. The center of the image was then extracted to create a 2.35:1 aspect ratio, in the manner of the then-current Superscope process. Unfortunately, it was poorly done, resulting in a large number of badly-framed shots; for example, the scene with the Flamenco dancers has a huge amount of headroom while their feet are cut off.
DVD-R comes with 2 pair of 3-D glasses, in color DVD case, wrapped in plastic!