This month, my Scientific American column tackles the new era of vertical video—videos shot and viewed as tall, thin rectangles, suitable for smartphone screens without having to turn them. It’s kind of a mess: Vertical videos look ridiculous on TV sets and computer screens, but traditional horizontal videos play tiny and goofily on smartphones held upright.

This isn’t the first time aspect ratios (screen proportions) have changed—or have given society headaches. Here’s a quick history lesson. (An aspect ratio is expressed as either a horizontal-by-vertical proportion, like 4:3, or as its resulting ratio, like 1.33. The smaller the ratio, the more square the picture; the larger the ratio, the wider the image.)

• Original silent film format (1892). Aspect ratio: 4:3 (1.33). William Dickson, working in Thomas Edison’s lab, used multiple frames of standard Eastman Kodak 35mm film to create a video image. Examples: “A Trip to the Moon” (1902), “The Sting” (1973), and all television until the rise of high definition.
• Academy Ratio (1932). Aspect ratio: 1.37. To add sound to movies, engineers recorded an audio track on a thin strip alongside the video frames, resulting in a slight shift of the picture’s shape. Example: “Citizen Kane” (1941).
• Cinerama (1952). Aspect ratio: 2.59. Home television viewing was depressing movie-theater ticket sales. To combat that trend, special theaters offered this extremely wide picture, created by projecting three standard 35mm images side-by-side onto a giant curved screen. Example: “How the West Was Won” (1962).
• CinemaScope (1953). Aspect ratio: 2.35. Twentieth-Century Fox sought a similar widescreen image without the hassle and limitations of the three-camera system—by squishing (distorting) the wide image onto standard 35mm film, and then re-expanding it when projected. Example: “20,000 Leagues Under the Sea” (1954).
• VistaVision (1954). Aspect ratio: 1.85. By rotating the standard 35mm film 90 degrees, VistaVision scenes could be shot on a larger area of the film, resulting in a higher quality picture. Examples: “White Christmas” (1954), “Taxi Driver” (1976).
• Todd A-O (1955). Aspect ratio: 2.2. The film itself was twice as wide (70mm), creating much sharper images at larger projected sizes. “Oklahoma” (1955), “Patton” (1970).
• MGM 65 (1957). Aspect ratio: 2.76. Another 70mm format. Example: “Ben-Hur” (1959).
• Super Panavision 70 (1959). Aspect ratio: 2.20. A refinement of MGM 65. Example: “Lawrence of Arabia” (1962).
• IMAX (1970). Aspect ratio: (1.43:1). Much as VistaVision sought to improve resolution and quality by running 35mm film horizontally through the camera and projector, IMAX runs 70mm film horizontally. Example: “To Fly!” (1976), portions of “The Dark Knight Rises” (2012).
• HDTV (1996). Aspect ratio: 1:78 (16:9). Engineers settled on this first-time aspect ratio because it was the geometric mean between 4:3 (standard TV) and 2:35 (an average of typical movie ratios), so that an HDTV set could display both kinds of video without much “masking” by letterbox bars. DVDs, Blu-ray, and 4K all inherited this shape, which is standard for all TV production today.

You wouldn’t think our history of variable aspect ratios would be a big deal; we can watch any of those movies on our TVs, tablets, and computers today. If they don’t fit the screen perfectly, black bars (letterbox bars) fill the gaps.