Mechanical Television - Aspect Ratios For Different Purposes

Aspect Ratios For Different Purposes

Some mechanical equipment scanned lines vertically rather than horizontally, as in modern TVs. An example of this method is the Baird 30-line system. Baird's British system created a picture in the shape of a very narrow, vertical rectangle.

This shape created a portrait image, instead of the landscape orientation that is common today. The position of a framing mask before the Nipkow disk determines the scan line orientation. Placement of the framing mask at the left or right side of the disk gives vertical scan lines. Placement at the top or bottom of the disk gives horizontal scan lines.

Baird's earliest television images had very low definition. These images could only show one person clearly. For this reason, a vertical, portrait image made more sense to Baird than a horizontal, landscape image. Baird chose a shape three units wide by seven high. Actually this shape is only about half as wide as a traditional portrait. You can imagine this shape this way: A typical doorway also has the proportions three by seven.

Instead of entertainment television, Baird might have had point-to-point communication in mind. Another television system followed that reasoning. The 1927 system developed by Herbert E. Ives at AT&T's Bell Laboratories was a large-screen television system and the most advanced television of its day. The Ives 50-line system also produced a vertical "portrait" picture. Since AT&T intended to use television for telephony, the vertical shape was logical: phone calls are usually conversations between just two people. A picturephone system would depict one person on each side of the line.

Meanwhile, in the US, Germany and elsewhere, other inventors planned to use television for entertainment purposes. These inventors began with square or landscape pictures. (For example, consider the television systems of these men: Ernst Alexanderson, Frank Conrad, Charles Francis Jenkins, William Peck and Ulises Armand Sanabria.) These inventors realized that television is about relationships between people. From the very beginning, these inventors allowed picture space for two-shots. Soon, images increased to 60 lines or more. The camera could easily photograph several people at once. Then even Baird switched his picture mask to a horizontal image. Baird's "zone television" is an early example of rethinking his extremely narrow screen format. For entertainment and most other purposes, even today, landscape remains the more practical shape.

Read more about this topic:  Mechanical Television

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