Indian heads and Carole Hersee

I am ridiculously sentimental about old media. The history of broadcast and recording is a source of endless fascination for me. I'm not entirely sure why, except I think there's something magical about being able to capture a performance at one moment in time and carry it forward so that millions of people -- some of whom weren't even born when the performance took place! -- can experience it for themselves. Virtual time travel, albeit slow unidirectional virtual time travel.

Back in the days of yore, televisions were very temperamental. The worst we deal with now is figuring out how to make our movies display in widescreen, so they aren't full of pencil-people. Early televisions were wholly analog, and there were an infinity of ways the horizontal alignment, vertical alignment, convergence, retrace, and maybe a thousand other things could be faintly, but irritatingly, off. There was actually a point to having a TV serviceman, who would come to your house and fiddle with the set until it displayed things you could reasonably watch (quality of the programming notwithstanding), rather than just some teenager who would come get your broken set and drop off the warranty replacement.

If you ask most people what's on television at 3:30am, they'll say "infomercials", but it's only been comparatively recently that television stations have run programming 24-hours a day. For a long time, most stations went off the air after the late-late-late show. Rather than turn the transmitters off, which is quite a production, they broadcast one of many "test cards": patterns meant to provide a signal that would allow the viewer at home to adjust their television set for optimal performance. Test cards varied by region, format, and network, but they generally contained at least one large circle (to test for geometrical distortion), some areas of fine black and white lines at various angles (to test sharpness and contrast) and, later, a colorful image or a set of SMPTE standard color bars (to give an indicator of hue and color temperature).

RCA's Indian Head test card is one of the more famous ones from the black and white era, whereas the BBC's Testcard F, incorporating a snapshot of engineer's daughter Carole Hersee, is one of the best known of the color era.  There do exist HD test cards, albeit not many of them; one of the most sentimental is Sky HD's recreation of Testcard F in widescreen HD, with a photo of Myleen Klass.

Though test cards are still routinely seen in countries where 24-hour broadcasting is not the norm, but in the US and a substantial part of Europe, test cards have been relegated to internal use at television production studios. Poignantly, when full-power stations in the US were required to switch to digital broadcasts, more than a few of them chose to go into the sunset transmitting a classic test card as their last analog image.