"Harry Bloomfield" wrote in message
news
Dave Plowman (News) pretended :
A B&W TV can't show colour - other than that of its phosphor. Assuming
you
are talking old CRT sets - not sure I've ever seen a B&W LDC, other than
tiny ones.

The BBC conducted some experiments in the 1960's, I think Tomorrow's World
might have been involved. Then of course all TV's were CRT, but I did see
a slight hint of colour, on a B&W CRT. Some saw nothing as I remember.

Yes indeed. It used different mark/space ratios of flashing to make the
effect. As a boy I made a spinning disc optical illusion which has four
circular tracks with different ratios. There is a youtube demo of it he
https://youtu.be/hf3KTsRRPLs (fast forward to midway to skip the prologue).
--
Dave W