How 16:9 Became the HDTV Aspect Ratio Standard: Dr. Kerns Powers and the SMPTE Decision

"The aspect ratios in common use are normalized to equal area and placed on a common center. A very interesting result was obtained. All of the rectangles are contained within an outer rectangle (labeled the aperture) with an aspect ratio of 1.77. They also fall outside an inner rectangle (called the reticle), which has the identical aspect ratio of 1.77. Thus we have the makings of a shoot-and-protect scheme in which both the exposed area and the inner reticle are in widescreen format, yet permitting releases in any aspect ratio in the range of 1.33 to 2.35. The fluff, or disposable exposure area computes to about 43 percent, exactly that obtained when shooting a full 35mm frame and protecting for release at 2.35. The disposable exposure area is distributed uniformly around the action area instead of being concentrated at top and bottom. After a very short debate, the proposal was accepted, the 1.77 value was rounded up to 16:9, and an unanimous vote by the working group established the new value as the standard aspect ratio for HDTV.

About a year later, during preparation of a recommendation for the Advanced Television Systems Committee, the value of 16:9 was reconfirmed by another vote of the working group, and the ATSC adopted the value to be included in the U.S. position before the CCIR for an international standard. The Japanese and the Europeans had preferred the 1.67 value but were persuaded to agree to the new value. Although several other parameter values for HDTV have not reached international agreement, the aspect ratio has been put to bed at 16:9.

Kerns points to additional features of the I6:9 aspect ratio

Other than the universal "shoot-and-protect” feature, there are additional potential advantages of this choice. The rounding up to 16:9 permits some interesting polyscreen displays in consumer TV sets equipped with 16:9 picture tubes, but displaying 4:3 images. A possibility for film production would be to capture images on 3-perf 35mm film at a full-frame aspect ratio of 1.78, using the above shoot-and-protect method, thereby saving some cost in raw film stock during shooting and editing. 3-perf film has been discussed in combination with 30 frame-per-second shooting as a method of balancing the 25% increase in cost of the film stock from the higher frame rate. Finally, the 16:9 aspect ratio would be appropriate to a new proposed Scope format with 1.5:1 anamorphic lenses, leading to possibly higher brightness and lower-grain presentation. Scope’s on-film aspect ratio of 1.18 would be retained.

While this aspect ratio choice came under later fire from the Hollywood production community, Richard Stumpf, then chair for the HDTV production standard work within SMPTE and vice-president for technology with MCA, recalls making repeated efforts to attract the Hollywood production people to come to the SMPTE meetings to make their desires felt. Lacking that input, the standard was arrived at by unanimous SMPTE committee vote (in the Academy of Motion Picture Arts and Sciences conference room) using the criteria noted above for the decision.