Why did some European countries opt for 441 or 455 lines?
Freedom of thought probably. Although the 405-line system was well established in Britain, there was no serious thought of international programme exchange before the war, so the need for total conformity was not a major factor. We have not yet achieved standardisation of computer operating systems or of driving on one side of the road, and there are always arguments in favour of whichever standard you favour. In theory 441 and 455 lines would give marginally better picture definition than 405 lines – marginally.
