Why was Test Card E dropped so quickly?
There is some confusion as to how long Test Card E lasted. George Hersee the BBC expert on Test Cards is reported to have said it was withdrawn on the first afternoon, having been shown in the morning. Other informed sources say it was shown for up to a month before being withdrawn. The objections were from the TV trade and were related to the us of sinusoidal frequency gratings, instead of the previously used “square” wave gratings. The sinusoidal gratings were ideal from an engineering viewpoint, producing a good signal to measure. However they appeared on most sets to be out of focus, leading to complaints.
