Re: Scary
There was more than just the test card.
During the rollout of coulor TV in the UK in 1967 or so, BBC2 carried a number of test programs, which I believe were called "Trade Test Transmissions". They were basically colourfull short documentaries, broadcast at fixed times of the day, so that TV installers has something predictable to set the colour up on the TV they were installing (Colour TVs were still mainly valve driven, and were fiddly to set up, took ages to warm up from cold, and generated large amounts of heat).
I happened to be ill for a while that year, and off school for a week or two, and I remember three of them. One was called "Ride the White Horses", and was about power boat racing, another was called "Skyhook", and was about helicopter cranes, and one was called "Birth of a Rainbow", about rainbow trout farming.
There were more, but I can't remember them. Wikipedia has a list.
Looking a YouTube, they have the one about rainbow trout, and some of the others, but not the other two I remember.