I'm fascinated by the old television test patterns, so it's no wonder that my Facebook profile picture is the image of the famous Indian head test pattern. A couple of my Facebook friends got all nostalgic when they saw it, so I thought that they would enjoy reading a little bit about the history of the television test pattern. What follows is the speech that I delivered on that very topic, at a recent meeting of my Toastmasters club. Read and enjoy! Wistfulness is not only permitted, but encouraged.
Remember the old TV test patterns? Many of us who experienced firsthand the heyday of television remember them. They were geometric charts, often with a bull’s eye design, that were transmitted onto television screens from the 1940s through the 1970s. Test patterns came on at night after formal sign offs by the television stations and the playing of the National Anthem. In those days falling asleep while watching the late movie was common and even pleasant. Less pleasant was awakening after the movie to the weird test pattern and the eerie sine wave tone that usually accompanied it. The sine tone was very similar to the sound of the emergency broadcast system that is periodically transmitted on our local radio stations. Not the sort of thing that, in any era, you want to hear in a dark living room in the middle of the night.
Test patterns have become a nostalgia icon, reminiscent of the days when television programming was wholesome, and TV-watching was so all-American a pastime that gathering the family around the television to watch Roy Rogers and to eat dinner from TV trays was practically patriotic.
But those odd bull’s eye patterns served a purpose other than to weird out viewers, or to instill baby boomers with wistfulness.
In the twenties test patterns, which at the time were called test charts, did not conform to any standard. But by the 1930s, broadcasters settled on a design that would accomplish two things: check the quality of the transmission from television studio to antenna, and allow viewers to adjust the pictures received by their televisions at home.
The archetypical chart used by NBC/RCA, the first television “network,” looked like this:
If the transmitter was scanning beams that were too narrow or too wide, the circles took on an elliptical shape. If the scanning of the beams was not uniform, the circles would be egg-shaped. These shaded concentric circles in the center were used to measure and set the contrast controls, which adjusted the amount of shading and depth.
The bars that shot out from the bullseye in four directions were called “definition wedges.” The horizontal lines were used to measure vertical resolution, and the vertical lines measured the horizontal resolution.
When a television set was initially set up in a person’s home, these defects were corrected by the installer using precision controls. But over time dials would shift, so the test chart would help the viewer to make adjustments of his own as needed.
Let me pause here and ask how many of you are laptop owners? Now how many of you have read the manual that came with your laptop? Now you probably understand why folks with televisions in their homes didn’t know how to use the test patterns. Although televisions came with manuals that explained how to adjust the TV controls using the test pattern, most users didn’t bother to read them. It’s interesting to note that this was the case even in the early days of television, when the test chart appeared on screen more frequently than the live programming. By the 1950s the test pattern was shown in the early morning or very late at night and most users randomly fiddled with the knobs and antenna hoping to somehow end up with a quality picture.
Those viewers who were paying attention to test patterns saw a lot of the famous Indian Head design. The Indian Head was created for RCA in 1939. No one knows how or why the design was chosen, but the Indian head is a cultural icon. When television stations switched from analog to digital transmission in 2009, many of them chose the Indian head as their final broadcast. The image has even been produced as a night light. An interesting footnote is that the original Indian head artwork was found in 1970 by a wrecking crew worker in a dumpster at a demolished RCA factory. He saved the piece for over 30 years before selling it to a test pattern collector. During the 1950s and 60s the Indian Head pattern was gradually phased out. At first it was shown for shorter periods of time, then was eventually replaced by the chart of color bars that heralded the era of color TV.
An interesting side note is that, at about the time the Indian Head test pattern made its onscreen debut, RCA was experimenting with transmission of a dimensional image. The earliest dimensional image to appear on the screen in the mid-thirties on NBC’s experimental station W2XBS was a rubberized model of Felix the Cat (the only object that would not melt under intensely hot studio lights).
In Third World countries, test cards are still seen because most television stations in those countries do not have 24-hour programming. But here in America in the 1970s, twenty-four hour broadcasting made test patterns obsolete.
The appeal of television test patterns, however, lives on. TV test pattern buffs can get all manner of goods imprinted with test patterns, including clothing, jewelry, doormats, laptop skins, shower curtains, and – not surprisingly – TV trays. If you are a do-it-yourselfer repairing a television you may need a test pattern generator to help you to locate a malfunction. Never fear! You can download the free test pattern software from the internet.