It's a fact: Television screens shrink when they're brought into the United States.
For example, if you buy a 29-inch color TV set in Canada and drive it across the border, it becomes a 27-inch set. But take the set back to where it was purchased, and it swells to its original size.Even though this sounds like somebody's idea of a bad joke, it's not. According to Video magazine, the difference in size comes from the way TV screens are measured in the United States, as opposed to the way they're measured in other countries.
The first TV screens were round, and their sizes were identified by their diameter in inches. When it became fashionable to mask off the screens into rectangles, the measure was taken from one corner to its diagonal opposite.
Eventually, rectangular picture tubes were introduced and were identified the same way, by the tube's overall diagonal measurement. This system is still used in most countries today.
But in the 1950s, the Federal Trade Commission decided that advertising the diagonal size of picture tubes constituted misrepresentation pointing out that the tube's external glass walls constitute one or two inches not occupied by the picture.
The FTC proposed the use of length-by-width ratios or the measure of the picture area in square inches. TV manufacturers objected, and more than 10 years of hearings and legal squabbles followed before a compromise was reached.
The compromise involved something called "viewable diagonal," which was defined as the diagonal measurement of the picture area, not of the entire picture tube. The FTC's order became law, and on midnight, Dec. 31, 1966, most tubes lost a little fat.
Since then, American tubes are identified with a "V" after the size designation, as in "27V," which is a 29-inch tube in Silesia, Upper Volta, Sri Lanka and just about everywhere else.