Why did 405 look so good?

[Synchrodyne]

Apart from poor UHF performance of some dual standard sets there's a psychological or perceptional reason. If you can see the lines sharply defined you tend to think the picture is sharp. Even if it isn't.

In the 1960s, most of the overseas TV programmes that came into NZ were, as I understand it, on film.  Most of those were probably originated on film, but allegedly some of the British programmes were film transfers from 405-line videotape.  I imagine that the transfers were done with spot wobble to ensure flatness-of-field and to avoid lininess, but the net result was visibly poor vertical definition.  This evidently applied to one popular Granada-origin serial-type programme, and its poor picture quality attracted adverse attention, with the above explanation (405 videotape-to-film transfer) for it being published in one of the daily newspapers.
 
That I think would be consistent with the notion that lininess disguised the relatively poor vertical definition.  And maybe that’s why spot-wobble did not become mainstream – it got rid of the lininess but showed the poor vertical definition.
 
I don’t think that many American export programmes were transfers from videotape to film, but a few were, and with those the black-fringing propensity of the image orthicon camera tubes that were widely used back then.
 
Also, the British and American TV programmes had differences in their soundtracks, as well.  In the American case, recording levels were high enough for there to be audible peak clipping now and again.  In the British case, peak clipping was avoided but hiss was more evident.
 
 
Cheers,
 
Steve