A still television picture transmitted outside normal programme hours and designed for use in judging the quality and position of the image.
〈英〉（电视）测试卡（非正常节目时间播放的静止电视图片，用于判断图像的质量和位置）
Example sentencesExamples
Practice varied from company to company - but the ten minutes of blank silence before the ITA test card appeared always gave a dramatic feeling of finality to the transmission.
Viewers started to get used to the idea that if they switched on their TV screens before 9 am they would have a programme to watch as opposed to a test card or a blank screen.
I still secretly believe that afternoons are the time for the test card and you shouldn't watch television when the sun is out.
As others have pointed out, it's like being whisked back to the 1950s, except that then the only thing on TV at 1.30 pm was the test card, although that was much more riveting viewing.
A full day of test card and music is unimaginable today - but television then was packaged as an evening activity, and daytime broadcasting was almost seen as vulgar and over the top.